Pursing a graduate or professional degree is an important decision that requires significant planning.
For students exploring graduate school options other than health and law, there are graduate school advising liaisons in each department. Typically, students should start the the process early to allow time for them to think about what they might like to do and why; then they can consider all of their options and ultimately prepare the best application materials possible.
Kaplan TestPrep provides free, online graduate practice tests in most areas (e.g. GRE, LSAT, MCAT, GMAT, OAT, DAT).