The best way is always to stop when you are going good and when you know what will happen next. If you do that every day ... you will never be stuck. Always stop while you are going good and don't think about it or worry about it until you start to write the next day. That way your subconscious will work on it all the time. But if you think about it consciously or worry about it you will kill it and your brain will be tired before you start.
Ernest HemingwayNo good book has ever been written that has in it symbols arrived at beforehand and stuck in. ... I tried to make a real old man, a real boy, a real sea and a real fish and real sharks. But if I made them good and true enough they would mean many things
Ernest Hemingway