Bluegill are just about in any Texas water body.
Right now they are active and some are sitting on beds.(Spawning).
During the summer months the gills love staying by structure such as docks,overhanging tree limbs,sunken timber,and large rocks. Fish boat slips and dock edges. Also fish by trees. I love using worms (night crawlers). Ultra light rod and reel,six pound test line,size six cricket hook with a size five shot and your are ready to go.
Gills are a very aggressive fish and you will know pretty fast if they are in the area.
Good luck and let us know how you do.
Side Note: Sunken brush piles and drop off ledges in 10 to 15 feet of water are also great places to look for gills.