Advice on moving to San Antonio

My fiance and I will be moving out to San Antonio from Waco in a few months when she starts graduate school at UTSA. We are looking for a place to rent that is within 30 minutes of campus, but don't know the good neighborhoods from the bad. Anything we should avoid or look out for? Any general advice from natives? We've only ever been to the Alamo and the river walk. Thanks!