Make starting cheap

Commit to ten minutes and give yourself explicit permission to stop at the end of them. The bargain has to be real — if it is a trick to get yourself to work an hour, it stops working within a week. Most of the time you carry on, because starting was the expensive part and you have already paid it.

Cut the friction around the start as well. Have the file already open, the desk already clear, the phone already in another room. Every step between you and the first action is somewhere the avoidance can get in.