What is the best way to profile/optimize google app engine application?

Question

Currently I am working on new App Engine application.

Unfortunately it seems that my application uses to lot of resources even for relatively small user number. So

Answer 1

Appstats: RPC Instrumentation for Google App Engine. It is being developed by Guido himself.

alt text http://img130.imageshack.us/img130/526/timelinea.png

EDIT: I believe AppStats will not work with Java, but there are some tips here.