Not Legal Advice: According to Golaketravis.com, as for things to avoid, don't drive the boat if you've been drinking on the water, and remember to keep your drinks in cans, no glass bottles.
Here are other "do's and don'ts" for boat safety:
Always have enough life jackets for everyone on board, and keep everyone under 14 wearing the jackets full time.
Also, keep a flotation device handy that you can throw to someone in the water if needed.
For more info about Intoxication And Alcoholic Beverage Offenses in Texas visit Statutes.legis.state.tx.us and for FAQ about boating laws visit tpwd.texas.gov.