Be a spectator: If you have the opportunity to just watch a triathlon, stand near the transition area and pick out a few people to observe and analyze. You’ll find examples of what to do and what not to do out there.
Try this at home: Set up a personal transition area. Run 10 yards toward your bike, put your helmet on and go. Put your shoes on while you accelerate on the bike. As soon as you can ride normally, relax for a second and start the T2 practice run, meaning do the same thing in reverse: Get your feet out of your shoes, approach the makeshift dismount line, jump off your bike, run to your spot and quickly get your helmet off and put your running shoes on. Grab your run gear and off you go. Can you do the whole thing in less than 10 seconds? Do it again and again until you can. The perfect place to practice this is a 400m track. After 200m you must be in your shoes, you have 100m to relax, and 100m to prepare to get off your bike. I usually start this practice two weeks before my first race. If you think this won’t help your overall performance, go back and check your split times in T1/T2—I’m sure the numbers will speak for themselves.