Don't take too many classes at once. That's the best way to make sure you do well. I learned that one the hard way. Don't forget that lab classes are a whole extra class too, even if it just shows up as one class on your schedule.
In a single semester I took
1) organic chemistry
2) organic chemistry lab
3) physics 1
4) physics 1 lab
5) micro biology
6) micro biology lab
MISTAKE!!!
I didn't really think about the labs as separate classes because 2 of the 3 labs were included as part of their lecture class in the course selection system. So when looking at my course list it appeared like I was only taking 4 classes instead of 6, so it didn't seem like too heavy a course load when I just looked at the list. So it didn't set off the alarm bells in my head that it should've.
I wound up with an A in physics, an A- in micro lecture, a B in micro lab and a B- in organic chem. So not too horrible, but not nearly up to my personal standards. And it really took a lot out of me and it physically messed up my health so that I ended up having to withdraw from the next semester.
If you're smart you'll heed my advice - err on the side of taking too few classes and having to stay in school a bit longer rather than taking too many classes which would result in poor grades, ill health, and might actually make you stay in school longer anyway.
i'm going to have to agree with this one here, although i did take 18 credit semesters with three science courses a couple times during college (and graduated a semester ahead of my peers). one semester, i had a bit of an episode and was in a bit of a panic after getting the dreaded F in an exam (i ended up with a B in this course, and passed all my classes).
but related to that was that i found a new study technique right after that exam, that was to draw the concepts about a week before exam time and put them on a blank sheet, so it would be a bunch of drawings crammed together, explaining different concepts. got an A next exam and worked for me the last year of college.
most of the time, i just review the notes about 2-3 times a week and it just sinks in eventually. my memory is pretty good, so i typically didn't study the 2 hours per hour lecture that was advised (it was probably closer to 1 hour of study for many courses, but i did squeeze in more study time for other courses, i just studied until the concepts sunk in, vary by mileage). for problem solving stuff, i would work out problems in the back of the book for practice.
other times, i would spew out concepts randomly and try to connect concepts that i learned in class to real life (ex. in botany class, i would try to id the parts of the flower, etc, and what they do while just walking across campus and seeing them). at one point, i actually did a rap on concepts, and it was pretty funny when i was trying to help a classmate understand some concepts.
i hardly used flash cards though, i found those mostly a waste of time, expect for right before the exam (1-2 hours before) to brush up on a few things, as i need time to really sink the info in, not whip by it when i'm trying to learn it. these are mostly to see mastery of skill.