1) Do the major your like (psychology), fulfill the pre-med prerequisites slowly, don't rush this. Although, it's not a requirement at most schools make sure to keep up with your math as it'll make physics and all lab courses that much easier.
2) Get involved in research, there's probably a TRIO program in your region as it lobbied in DC, so there's probably a under represented (UR) outreach program meant to get URs into pipeline research projects -- try to get something in psychology. I used to work in an office for that, so I know they exist. You don't need to publish necessarily, just present a few posters, try to travel on stipends etc. It'll give your application some weight, and you'll learn a lot.
3) Start a curriculum vitae now. It'll make applying easier because you don't have to try to remember what you did and why it mattered.
4) Some people won't like you -- this means you have a fan club. Some people would give me dirty stares as I turned in my orgo exams extra early, you can use that extra time to party (see 7) because you didn't cram like others.
5) As someone mentioned, get a mentor. But, if you have a crappy mentor don't stay with them. Your campus probably has something called the Office of Undergraduate Research, you can start there or talk to your professors. But, if you talk to that office first you can be more strategic about who to take courses with to build relationships in the first place.
6) Use office hours, but do so wisely. Work your butt off to answer questions, show your curiosity in the office hours -- I was offered my first physiology project this way.
7) Make good friends who are also scholars in mindset, they'll understand you for you.
8) Don't cram. Nothing in undergrad really goes all that deep (that's why there's PhDs and post docs), so you're always learning a good overview. But this also means there's just a lot of information, none of it is that hard if you don't cram.
9) Do your own research, either way it's your ass on the line not anyone one here, your advisors, or friends.
10) Get tutoring, you're paying for it already in your student fees. If you're doing fine, then learn some advanced stuff from your tutor. People used to come to me for orgo tutoring who were doing fine, but they just wanted to know how to do those end of the chapter problems to finish things off etc, I didn't mind it.
11) Work your ass off for the MCAT, don't think you'll make up a bad GPA with a stellar MCAT.
12) Apply early!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!11!!!!
