My favourite tip:
Some people get stiff and unhappy writing because they think they can’t manage to write how it feels to have an adventure, or to be in the middle of very fast, exciting action. This is nonsense. Everyone knows.Read the rest on her website.
What you have to do, if you are stuck this way, is to stop thinking in words and then shut your eyes and think how it would be if you were the one having the adventure, falling down the cliff or being attacked by a vampire, or whatever.
You'll know at once. Then you simply put down what you know. It may come out queer, but queer is good where actions and feelings are concerned.