Really not enough information given to help you out much. There is a LOT of different types of fishing to be done in Galveston, but not knowing your equipment makes it tough to know what to suggest. Fishing on the beach is different from fishing the bay, etc. Under the circumstances, my advice would be to hit one of the piers. They will have the right bait and you can rent tackle if you need it. If the fish aren't biting, go upstairs to Jimmy's and grab something to eat and drink some beer. You'll have a good time. Your other good option would be to take a charter boat, but that will cost you a little more.