Somewhat the same as dfletch and greende, although I don't blow out the traps, only used the pink stuff in the traps with enough that goes into the gray and black tanks after those have been emptied as best I can get them.
Also as pointed out, do not forget to start with emptying the fresh tank, then run your onboard water pump until no more water. Also, if you have that clear strainer on the water pump, open that and get the water out. Black flush, outside shower, water heater cutoff are all easily forgotten.
I actually just got back from a trip and have no plans to take our TT out again this year. Since my TT is at a storage facility over 30 minutes away, I'm going to winterize today also just so I don't have to stress about getting it done later. Since I only use air in the water pipes and if I need to use the trailer again, it is easy and don't have to dewinterize to get that nasty pink stuff out of the pipes. Blowing out the pipes is actually pretty quick.