I have a lot of tips that work for me. Some easy ones--don't think of doing the entire thing all at once, just the first step. For example, don't think I have to write a whole paper; instead, think I'm going to write my introduction. (Or even just the first sentence of the introduction.)
You could also try visualizing how good you will feel when you're finished. Or think about the good part about the work you need to do.
Stuff like that.