Transition Set up:
You don't need a ton of room in transition. Bike in rack. Helmet (with glasses inside) set on bike. Some races want you to put your helmet on before touching your bike - others you just need it on AND BUCKLED before mounting the bike. Usually I tuck my bag under my rear wheel to conserve space.
Transition gear laid out on either mat or small towel (not a beach towel - some of these racks are packed and no need to hog space).
I lay out my stuff in the order I need it front to back. Bike shoes with socks tucked in or laid on top. Yeah, yeah, lots of elites and elite wannabes race without socks, but I'd rather take 3 seconds to put on socks than limp in with blisters. One of these days maybe I'll make the leap to sockless, but for now I'm putting on socks.
I generally try to place wetsuit where the bag is located in this picture (unless there's room to hang it on rack). You want to avoid setting the wetsuit where it will get your running shoes wet.
Running shoes behind bike shoes. I usually place running cap with race belt, watch and sunglasses tucked inside next to running shoes. Coming in for T2 off the bike I swap shoes, dump my helmet and cycling glasses, grab the hat and go. I can put on my running sunglasses, race belt, watch and cap while I'm moving.
Once I've got my stuff set up and prior to leaving transition I make sure I put on sunscreen, body glide and heart rate monitor. Where to put the glide you ask? Any place that your wetsuit rubbed when you practiced in it - because you all practiced in it . . . right! Back and side of neck and lats are common locations. You can also put it on your lower legs to help with removing the suit after swimming.
Make sure you have your goggles and cap before leaving.
No rain in the forecast this weekend but I usually have plastic bags that I can tuck my shoes/gear in (one for bike, one for run) if there's ANY chance for precip. That way I can at least start each leg with dry gear. I include a second pair of socks as dry socks feel awesome after a long bike (not really necessary for shorter races).
Have a great weekend of racing! This is the fun part.