I personally have tried these with success.
do at least 3 routes before I get on anything hard. Preferably more. I'll climb the same 10 or 11 three or four times if need be.
warm up on my project, to relearn moves, just bolt to bolt.
warm up on routes of similar style as the project you are working on.
I think you have to be flexible. Listen to your body. Get in tune with when you are ready to perform at your best.getting a slight pump and then I wait 30-40 minutes before getting on something hard.
If you get into a regimented warm up and you don't pay any attention to how you are feeling. You could cost yourself a send or worse you could get injured.