Take more BS classes, because nobody cares what classes you take, just your GPA.
Quoted for truth. As someone whose been accepted this cycle (after going through grad school and a "gap" year) no one cares about what classes you take. And if, by chance they do that's a low on their priority list and easily explained away by "I wanted to get involved in more ECs/ research/etc etc".
I bought into the whole "you have to take harder classes because you're a premed" thing and it just sucks. Seriously, why did i have to take the engineering calculus and the physics majors physics?? Take the easiest of these more difficult classes you can fine - their still calc and physics. I saw my friends breeze through these with A's with 1/2 the material and 1/4 of the work whereas I struggled to get that B- with the really hard engineering calc class that drug down my science GPA.
Also, I would highly recommend taking the MCAT after your sophomore year if you plan on going straight though. Right after you finish taking ochem and physics (physics was my hardest section), and you'll probably have a bio class or two and only a year out of gchem. Why wait an extra year and have to work to relearn all that physics/ochem crap?? Get a cush research job for a professor (doesn't matter what) for 10-20hrs a week, and study for the MCAT all summer (because you won't have to take it earlier in the year in time for the app cycle) and take it in August before you go back. Bam. If you score great then you're done, and the MCAT will last you by the time your ready to apply the next cycle. And, if you fail, you'll have a WHOLE year to improve/identify weakness/ come up with a study plan (use EK btw, don't blow 2Gs on a kaplan course). The two most important things in your app are GPA and MCAT. Then comes the personal statement and ECs. Don't sacrifice your GPA/MCAT for ECs/research - those are easy to make up - GPA/MCAT not so much.
College is a blast. Get involved in activities you enjoy, gain some leadership experiences if possible but don't stab people in the back to do so. It's not the end of the world if you don't get to be the bio society president (side note: major in something other than bio - do you really want to take classes on plant physiology??). Be humble in your journey, help people out whenever possible and network your ass off (without being annoying). These things will open doors for you that you never thought possible.
TL;DR
-ratemyprofessor.com will save your life (and your GPA)
-Take the MCAT after your sophomore year if possible, study all summer and knock it out of the park.
-College years are the best years of your life so enjoy them. Just don't "overindulge" to much.
-Be humble, network and above all don't be a tool.