There are two ways to vote early in Texas: in person and by mail. Either option will eliminate waiting in long lines on election day. Early voting generally begins 17 days before an election and ends 4 days before. If the 17th day before election day happens to land on a weekend, then early voting begins the following Monday.
For more information visit: http://elections.bexar.org/EarlyVote/earlyvote.html