The best advice I can give for possibly receiving a full-time offer is to show up to work on time everyday, work hard and produce quality work, be personable and keep a positive attitude, ask appropriate questions, and try to make as many connections as possible. The more of a positive presence you have in the office, the more likely the firm will want to hire you full time.
Complete your work accurately and on time. Ask questions when necessary but solve issues on your own that can be researched. Have a positive, ready-to-learn attitude towards the task. Improve upon your mistakes and pay attention to the feedback provided after each engagement. If you show your commitment to learning and dedication to your work, GT will most likely offer you a full time offer. Best of luck!