I'm interested in learning more about estimating projects. It seems like its largely based on the client.

Right now I'm getting killed on a project for a designer's personal site. She is nitpicking the site to an extreme degree, and pushing the envelope on gray area. I'm spending two or three times the time I bid on it.

I did another project this month where the client was easy going, and it was finished in half the estimated time.

Does anyone have any insights on this? Are there any good resources on learning how to estimate and manage projects?