Oh the pressure...

So. If I'm trying to work on an important project I get all tied up and can't think of any ideas, but if I'm just writing nonesense then I come up with lots of awesome stuff.

I think it's my perfection complex flaring up.

Any ideas how to make it go away?

keep the fact it's an important project as far back in your mind as you can. Treat it like any other... random idea which isn't going to go very far. And just like, write. Randomly. At least, as randomly as possible.

24 hours later (or whatever time you feel is appropriate), look at it again and apply edits where needed.

My two cents.

I find that planning things out really helps me to keep that important project manageable. It's easier to break the project down into manageable chunks and see what needs to get done when and how.

With that said, it's a good idea not to make the plan too rigid. Something may come up that completely wrecks the plan, like a crucial new piece of information or a family disaster, and you need to give the plan (and yourself) enough freedom to adjust to such things.

In any case, procrastination is a big NO. XD The sooner you get the project done, the more time you have afterwards to relax and have fun. Or, if everything decides to go to Hell in a hand basket (it happens), the less you procrastinate, the more time you have to fix things and make them perfect.