All great advice! As Tore suggested, listen to Personal Genius before you sit down to study. You sound unsure about your abilities which is of course a natural and common feeling, especially going back to school after several years.
Paul Scheele refers to the Personal Genius Paraliminal as the self-esteem supercharger for students. Listening will give you confidence along with a relaxed yet alert state that is ideal for learning. And remember, if you simply listen to a Paraliminal without first stating your goal or without having a purpose in mind, you most likely will only receive relaxation from listening.
Good luck!
p.s. Get Around To It is a great "stick with it" tape.