Tip #1: Write.
Some days words, ideas and concepts flows off your fingers.
Other days it feels like you're a Neanderthal attempting to write a doctoral thesis. On those days I've found that it is important to keep writing. Get your thoughts out for the mere sake of getting them out (as incoherent as they may be).
Note: I wouldn't 'publish' on the 'Neanderthal-writing' days. (Unless of course you are a Neanderthal, then I'd love to hear what you have to say.) Normally the better days are right around the corner. Make sure you have one of those before you share what you wrote with the whole world.
Tip #2: Pray. This is actually tip #1, but I was worried you might stop reading if I put it first. Invite God into the process of what you're writing.
What tips do you have for writing? (Be it for school, pleasure or work?)