Take breaks, look out side to clear your eyes then glance at your sculpture and note what you first notice. If you hit a wall with it cover with a bag and walk away! I sometimes leave sculpture wrapped for months. I check regularly to mist with water and see if I can move forward again. Taking photos can be a good way to get some perspective. Ask others ‘what they see’ and compare that to what you want them to see. A dog that looks like a donkey has too big a head for example.