I'll give my experience:
Make sure there aren't any leaks. Get some slicks, change the oil because you'll be beating on the car all weekend, and run the motor cool, but with oil hot.
Clothing - what should I wear?
if you run a 13.99 or faster you need to bring a helmet. I'm sure you have to wear a set of long legged pants regardless of the ET you run.
Water..........
Warming up the tires - how much, how often?
Well, you should only need one burnout per run. It is VERY key to match the temperature of the tires to the track temperature. If the sun's beating on the track then it needs a long burnout. If it's cloudy then a shorter burnout needs to be made, but enough to clean the tires off.
Pull in slowly and turn the top set of bulbs on, in which is called "Pre-Staging." For etiquette reasons, wait for the other person to Pre-Stage. Then start pulling forward slowly again, once again, turn the second set of bulbs on and you will now be "Staged." Now prepare to launch.
Whenever the front tires trip the beams. If you leave before the amber starts then you wont get an ET reading.
Stated above. They set the time to .000 for noobs, but partly because LED's are about .030 quicker (more accurate) than the incadescent bulbs. They aren't as widely variant at night also. Expect .010 quicker at night time as opposed to incadescent's .020-.030.
I would also like to note that not every lane is the same. Each of the lanes have their own set of rollouts. Part of lane choice in drag racing.
When should I launch the car
This is entirely up to you. Some people see different spots with the tree's. I can see early amber, solid amber, and late amber on each of the three bulbs. My father can only see early (compared to what I see). Find the spot on the tree your car can get the best RT at consistently then change the car accordingly, NOT YOURSELF!!!!
What RPM should I launch at? auto and manual
Depends on your car. Slicks, DR's, or street tires. For slicks you might want to start out at maybe 2500. My Car likes about 3500 althought it's a five speed. If you have an auto, just leave against the converter.
Depending on the power band of your car determines this. My car ran the fastest when I shifted at 5500 before I went internal and it made peak power at 4300rpm. Just make a couple of runs to see what your car likes.
What does my 60' time tell me?
Amount of traction, if the back tires tripped the beams cuz your front end didn't come down before the cones, or just plainly if you need to start modding drivetrain.