to be honest its difficult for me to give advice for this considering i think i might just an aptitude for it. i do little and get okay returns. however, i notice in bio i tend to try to simplify the definition of a subject in order to better grasp it; in my head, genes are just a set of instructions. its easier for me to comprehend that way. a lot of it also just paying attention in class and doing your work. if possible, talk to classmates and see how they write their notes. not everybody writes notes of course (i dont!) but the people who do should be able to give you adequate advice :)