There is a lot of good advice on this page. Pick three things you want to work on this semester.

Read

40 Ways to Be Successful in School: Practical Tips for Students by Daniel Wong

More Quick Advice

Be friends with your professor. The X-Factor Is Making Friends With Your Professor by Brian Robben
Find a friend in the class. In some classes, you might find friends in your study group, but you should have someone you can talk to about the class. It makes it a much more pleasant experience, and it gives you someone you can reach out to when you need help.
Be open to feedback. When the instructor gives you feedback, read it, and take it seriously. Look at feedback as a golden opportunity to learn. Ask your instructor where they give the most feedback in the class.

Advice from Former Online Math Students

We surveyed math students at the end of the course and asked what they wished they had known at the beginning of the class. Here are some of their answers.

I was pretty nervous about getting back into a math class after so many years, but with the way the content is presented and with the available help, I wish I would have done this a lot sooner. (MATH 100B Student)
[I wish I had known to] make time daily to do the work, instead of trying to do it all at the end of the week. (MATH 101 Student)
Ask for help. (MATH 101 Student)
Making a better schedule for getting assignments done. (MATH 101 Student)
I wish I had known a little better how to manage my time better. (MATH 101 Student)
It is important to give yourself plenty of time to complete your homework. (MATH 101 Student)
I wish I had known to look through the entire week when it first opened instead of just going through it at my own pace. (MATH 101 Student)
I wish that I had made use of the tutor resource sooner. I knew about it but didn't reach out until mid-semester. (MATH 108X)
At the beginning of this course, I wish I had known to take notes on the specific wording and details given to us in the lessons. It is often necessary to recall the exact working in order to answer the quiz questions correctly. (MATH 108X Student)
I wish I had known how much work, time, and practice it would require. (MATH 108X Student)
Exams are weighed heavily, set aside time to review before you take them. (MATH 108X Student)
I wish I had known that a lot of this course revolved around group work. (MATH 108X Student)
It is okay for me to not fully understand something all at once. Real and genuine learning comes through time and hard work. (MATH 108X Student)
[I wish I had known] that I could schedule a one-on-one tutor right away. (MATH 108X Student)
Plan ahead and make sure you [have] enough time to not feel rushed. If you can find some way to apply it to you, it will make it more enjoyable. (MATH 108X Student)
I wish I had known that it was okay to ask dumb questions because chances are, there are other people struggling with the same things, and you can all benefit from it. (MATH 108X Student)
I wish I had been more excited! It's been a great course, and I misjudged it because I have always had a hard time with math. I was pleasantly surprised. (MATH 108X Student)
I wish I had known how to manage my time better, so I was not always rushed or stressed about the work I had to do. (MATH 108X Student)
At the beginning of this course, I wish I would've known that really taking in what you read is very important. Although that may seem obvious, at the beginning of the class, I was just reading the text to check the box pretty much. After a couple of weeks, I realized that I would be a lot more successful if I actually absorbed everything. I started taking notes and stuff, which made everything a lot easier. (MATH 108X Student)
Keep up with the assignments, and don't procrastinate. (MATH 112X Student)
Taking effective notes of new concepts along the way would have made it easier to study for exams. I also wish I had engaged a tutor earlier in the class. (MATH 221A Student)
Just make sure to continually review material. (MATH 221A Student)
It isn't that scary! There are lots of people who are willing to help you! (MATH 221A Student)
I wish I could have realized how easy it was to meet with the tutor and ask our teacher about mistakes I made on the tests. (MATH 221A Student)
I wish I had known I didn't have to be afraid of it. Everything I needed to succeed was built into the course. (MATH 221B Student)
It is super important to keep up on everything and not skip any lessons or group meetings. All of the material is cumulative, and missing even just one meeting makes a difference. (MATH 221C Student)
Breathe! (MATH 221C Student)
It would have been more helpful if I was to write the core equations and concepts learned and rules learned weekly instead of before each test. (MATH 221C Student)
Doing well in this course is totally possible. Everyone has a personal experience and just because some people struggled doesn't mean you will. Don't defeat yourself before the course even starts by thinking that it's impossible to do well. (MATH 221C Student)
I really didn't even know what to expect from this course. I knew it was going to be challenging. The Lord had His hand in everything about it. It was a huge blessing the timing of when I took this course, who my instructor was, and the other students that I would be in a group with. There actually wasn't anything I wish I had known before. However, I am a much better person after taking this course and getting to know the great people that I have come to know and call my friends. I learned a lot about myself by taking this course. (MATH 221C Student)

Advice From Your Teachers

Read the advice from these instructors on how to be a successful student. They have been teaching a long time, and they know what they are talking about.

Bonnie Chapman - MATH 108X Instructor
I notice that my A students are also my students who submit assignments first. So my advice to students is to jump on the assignments immediately. Waiting to the last minute erases the chance for extra help if needed!

Michal Ramos - MATH 112X Instructor
While there are a lot of pieces of advice we can offer students, the biggest one I've found to be helpful is to tell them to ASK QUESTIONS. The more questions students ask, the more comfortable they will feel about their new classroom experience.

Alisha Oldroyd - MATH 108X Instructor
My successful students read announcements and feedback. I've discovered over the years that some students don't know the difference between the course material that every student sees and what is just for them, personalized by their instructor. Anything that could help them learn that the announcements and feedback aren't just a regurgitated version of what's already in the course would really help them!

Ian Wagner - MATH 111 Instructor
I've noticed that my best students...

Get oriented to course structure and routines early on
Self-advocate when needed and are specific about the help they need (for example, no vague emails at 2:31 am containing only the words "I don't get how to do it").
Read the announcements each week and know where to find answers to common questions.
- I'm often amazed at the questions I receive from students that would be answered by simply reading the announcements and learning the basic routines early on. I create my announcements on trends I'm noticing and things they really need to know, not simply as a "check the box" type of exercise.
Use available resources including their group (as appropriate) and additional resources provided by the instructor.
Use MML effectively as a means of skills development and feedback before being assessed (not sure if MML is used in all classes, but I think it's great!).
"When the time to perform has come, the time to prepare has passed" (thanks, President Monson!) take time to verify understanding before and after assessments.
Read feedback and learn how to fix their mistakes (i.e. don't make the same mistake on future assessments that they made on past assessments).
Get started early so I have enough time to help them as needs arise and give their brains time to absorb and make sense of the material.
- Seconding what was said earlier about getting things done early, not only does it limit our time to help them, but the brain doesn't work well under stress when it's 11:47 pm (MST, of course) on Saturday evening and that inevitable tech problem we warned you about is about to make your test late. It is still amazing how many students email me on Sundays with a problem to solve, usually related to an issue that could have been resolved if they'd started earlier.

Pete Sallay - MATH 215 Instructor
In my class, I have seen most students fit into two categories; "haves" and "not ready test."
"Haves"

The "haves" will log into the course regularly.
They seem to follow a calendar appropriately and ask for help or clarification when needed, willing to meet course expectations like group meetings.
They seem to put in the required amount of time each week and are okay with putting in a little more when needed and follow technology expectations like using an appropriate level of a calculator.

"Not ready test"

The "not ready test" seems to do the opposite of the first group.
They try to do the work on the weekends or just a few days a week.
They seem to not know when deadlines are supposed to occur or assume they don't have to follow deadlines.
They don't ask for help or respond to questions when emailed, or phone calls are made.
They avoid group meetings and try to "lone wolf" the course.
They try to put 1/2 as much time as needed (mainly due to working on the course on the weekend).
They also seem to try to do things differently than taught.
Students in this group will complain about how they are expected to work problems. There seems to be a frustration that they can't use shortcuts or outside websites to do the math of the course.

Kristin Hess - MATH MATH 109 Instructor
Sometimes I ask my students to share (as part of an introduction) to share advice with each other about success in online courses. Here are some of the ones I have seen repeated:

Skim the course and put the due dates from the course schedule in your phone
Work ahead
Ask questions when you don't understand
Log in to the course at least once a day (except Sundays)
Read the course announcements each time you log into the course
Double-check everything to make sure you haven't missed any assignments
Practice makes perfect. Practice everyday

Erin Summers - MATH 112X Instructor
In my class, the students that succeed are the students that utilize their groups. If a student has a group that works hard and meets regularly, they do much better. The students that do well also read the announcements, check into the course regularly, and do the daily assignments. And the students who do well take advantage of any opportunity to learn and master the concept.
The students who struggle don't respond to emails, they fall behind (sometimes in the first week or two of class) and seem to have the mentality that they will catch up later. They also avoid group participation and don't read announcements or really look at the feedback from their exams.

References

How to Study Math by Paul Dawkins

The 15 Habits of Top College Students by Lynn F. Jackobs and Jeremy S. Hyman