From 7 creative principles of Pixar:
1) Never come up with just one idea. Regardless of whether you want to write a book, design a piece of furniture or make an animated movie: At the beginning, don't start with just one idea - it should be three.
The reason is simple. If a producer comes to me with a proposal for a new project, then usually he has mulled over this particular idea for a very long time. That limits him. My answer always reads: 'Come again when you have three ideas, and I don't mean one good and two bad. I want three really good ideas, of which you cannot decide the best. You must be able to defend all three before me. Then we'll decide which one you'll realise.'
The problem with creative people is that they often focus their whole attention on one idea. So, right at the beginning of a project, you unnecessarily limit your options. Every creative person should try that out. You will be surprised how this requirement suddenly forces you to think about things you hadn't even considered before. Through this detachment, you suddenly gain new perspectives. And believe me, there are always three good ideas. At least.
2) Remember the first laugh. A big problem in the creative process is related to the enhancement of your ideas," cautions Mr Lasseter. "Revising, retouching, refining is very important, but it carries a danger.
"If you have a story, a joke, a thought, which you write down, it loses its effect over time. It wears itself out. When you hear a joke for the second time you still laugh heartily, on the third or fourth occasion already less so, and when you hear it the hundredth time, you hate it.
I say to my authors: 'Take notice of the first laugh, write it down if necessary.' This may at times be bothersome, but it is important. Many times, good things got lost because people could not remember anymore how it felt when they heard the idea for the first time."