a few tips:
Don't go on about being pre-med. In my opinion, it is arrogant to say your "premed" until you actually start applying to med school, so don't talk about the dubious ambitions you share with a good percentage of your classmates. Stay open to other fields, professors like this, and more importantly, you can't be sure of being anything yet. The more mature you are, the more the profs will like you. This means being considerate, reserved, and punctual. Handwritten thank-you notes/letters are almost a lost art, but they are a powerful way of showing you care.
Chances are you share some hobbies with your profs. Running, raquetball, cuisine tastes, etc.. doing sports or ec's with students helps revive youthful nostalgia for profs, and you get to know your professor better too. It is hella hard to find a reliable babysitter/housesitter nowadays too. Especially lunch (that is, once you are friends) is one of the best ways to find out more about them.
Stay away from professors who rub you the wrong way, especially if the feeling is shared by others. Generally tho profs are awesome, feel free to visit during office hours. There's something unique to collegiate life, talking about Blake with a professor, in their expansive study, while overlooking a tree-lined avenue full of students heading to class. Maybe this is the one stage in our lives when we are most pluripotent, capable of doing anything, becoming anything. And none of it, however distal to your final destination, will be in vain.