What do I need to do in order to get an A in college?

Speaking from experience I'm going to approach this from a "do as I say not as I do" perspective because when I was an undergrad I didn't apply myself like I should have and graduated with a 3.01 GPA which is basically a B. I made up for it years later when I got my MBA and graduated with a 3.67 but I wish I had more focus back then. So if you really want to shoot for A's in every class and get that 4.0 GPA you'll need to do the following, in my opinion:

1. Make your grades the priority, not a priority. This means that your #1 goal should be on doing whatever is required of you to get that A. Some professors will be tough and you will have to bend over backwards to get it but if that's what's necessary so be it. In addition, take advantage of any extra credit when/if it is offered. You never know when you may need it.
2. If you need help with a course don't wait to ask for help! Take advantage of the professor's office hours and sign-up for tutoring if necessary. If you see someone in your class who seems to grasp the material really well ask them if they would be interested in forming a study group.
3. Keep parties to a minimum. At college there will be a party somewhere every single weekend. I'm not suggesting you have no social life but you have to be realistic and understand that you can't party every weekend  and get good grades. Some of those weekends will be spent in the library working on papers.
4. Be careful who you hang out with. If you associate yourself with high achievers, their study habits and characteristics will rub off on you. Hangout with a bunch of party animals or underachievers and your grades may suffer.
5. Write up a schedule, not just of your classes but also your free time. Having a set schedule when you know it's time to study will keep you on track and focused. That being said, you will need time to decompress and relive some stress so join clubs and organizations you may be interested in and go to the school's exercise room to stay fit.  Studying too much will lead to burn out.
6. Don't sacrifice sleep! In college everyone wants to stay up late and socialize. There's nothing wrong with that as long as you don't make a habit out of it. You need proper rest so you can stay awake in class.

I'm going to give you an answer that I think others may not. The obvious stuff is to maintain good habits, good study habits, good diet, etc.. Then a good idea is to have a pact with friends to support each others' good habits, such as respecting schedules and sleep time and minimizing goofing off.

The other thing I'll say is to once again beat the drum, as it were, for matching your personality to your studies and your choice of major. I see many students choosing majors for reasons that are, to my mind, insufficient at best. These are choosing a career for prestige, for family and friend pressure, for salary potential and the like. The problem with that is something that most will agree with once it's said. That is, we tend to be good at what we like, and we tend to like what we're good at. This is a recipe for happiness. It's also valuable to realize that our lifestyle and spending habits can accommodate a wide range of income, and bad lifestyle and spending habits can exhaust just about any level of income. Add to that that being unhappy or plain bad at a high salary or high prestige occupation can get real old real quick, and as you get older, these tend to mean less and less. And as the saying goes, "You can't take it with you". (Besides, where would you put it? :-) 0

So here's where I mention the Personality Assessment Survey test, like RIASEC. Check with employment bureaus, occupational counselors, college advisors, and search the internet for one of these tests. The idea is that the test matches your answers to those of people in many careers and occupations that are happy and successful in those occupations.

The end result is that you will be more confident that what you're working on is as good a match with your personality as can be expected, and you can keep the results in mind when choosing not only a major, but individual classes. All of this together, along with continual contact with your professors and their counseling, will maximize your ability to get good grades.