writers block

so i now have 20 participants... enough to start writing up. i've been putting off writing my dissertation as i thought "well, i don't know what to write about until i know what tasks work..." (oh the joys of developing a novel battery!). the problem is... i just can't bring myself to start writing. i always seem to find something more "important" to do. the procrastination is getting stupid now.

i think that i seriously have writers block. tips to overcome this would be greatly appreciated!