deactivate the enableviewstate option for the controls where you don't have
to store the state.
for example, a menu, a simple list without any sort/select option authorized
(no need to keep information during a postback). deactivating the viewstate
for these controls reduce the size of the page.
Lookat the
http://localhost/folder/trace.axd file to identify which controls
produce your viewstate.
if you use .Net Framework 2.0, deactivating the viewstate for a grid keep
the sort/select commands, while in 1.1 the entire state for the grid must be
saved in the viewstate. (same thing for most of the controls in the v2.0)
There is more options, likestoring the viewstate on the server side,
applying some code to store only the requiered information in the state (but
you have to repopulate your controls) etc...