What are common errors in composing a thesis statement?

Many people choose a statement and go out to prove the statement. In doing so they frequently find that after being educated in the topic the may not agree or lack interest in the original view point making for a difficult write up.

My suggestion. Start with a general topic and research it. As you find things that interest you, focus the search more and more until you find something that you can write about forever and feel strongly about.