Q1. I am desperate. I don't have any ideas for my dissertation. What should I do?
Let me start with what you should not do. Do not attend too many seminars in your own field. Otherwise you may simply end up adding a comment to the existing literature, which is mostly made up of comments on previous comments which were themselves only marginal comments.
If you want a good idea, look at the world around you or take courses in other disciplines. Some of the papers in my own dissertation (like my 1979 paper on a principal-agent problem with moral hazard and an infinite horizon) were thought of while daydreaming in some law courses I took. Keep reading . . .
Source: Mostly Economics (via Mankiw's blog).