I recently had to deal with a number of grant applications, which were definitely stressful. I was sure that I would mess up in some way, and actually I did: I included a recommendation letter for one grant in the application for another. Oops!

Most of your tips are things I realised myself during the application process, but I probably would have been better off had I read these tips beforehand, so thank you for sharing them.

My personal strategy is to double-check everything (though I've seemed to have failed at doing that in this case).