A lot might depend on what has gotten you this far. You probably know what works for you by now...
My best advice would be to talk to (
successful) upperclassmen at your school. They can tell you which profs test from the book, which test from PowerPoints, which test from hints they give in lecture, etc.
As far as lecture attendance, again, ask people who did well in the course. Some teachers give many hints as to what will be emphasized on exams to reward students who attend. Other teachers are not very effective or interesting lecturers and test straight from their PowerPoints anyways, so it may be low yield to attend the lectures. It is important to weigh the quality/understandability (if that's a word
) of the textbook against how effective and intelligent the lecturer is. It's unfortunate, but some teachers are just up there going through the motions while other profs are excellent and can make the subject seem interesting, understandable, and applicable.
Personally, I attend as many lectures as I can simply for personal enrichment. That might sound dumb, but I like to ask questions, and why pay so much tuition money for the teacher's expertise in the subject and then not utilize that in your learning? Also, being in lecture will generally keep you on pace in the course; it's much easier to fall dangerously behind on the reading and material for a class if you skip its lectures.
Most of all, keep in mind a sense of professionalism and the relationships you are creating. Most professors realize that a significant number of students will skip classes when a big exam is looming in another class, but, for the most part, the professors have to be there and expect good students to do the same. How likely do you think a professor is to write you a strong recommendation letter for a clerkship/residency if they couldn't even pick you out of a lineup because you only showed up on test days lol?