Render Optimizing?

Does anyone have any tips on speeding up render times? Blender can do things beyond anything I ever thought a free software could, but many of the really interesting stuff takes a while to play with.

“I wonder what this does?”
render
eat lunch

"Oh! That was wonderful! But it would be better if . . . "
tweak
render
study for a half hour
check back
*study for another 15 minutes. . . *

I’m running windows xp with an athalon64 processor and two gigs of ram. Is there something I can do to improve render times? Or any sleight of hand things or hidden considerations that a noob like me probably wouldn’t know yet?

What did you discover to help render times in your learning of Blender3d or 3d rendering in general?

This will probably help if you don’t have it set, in the Output panel under the Scene buttons (F10), make sure that your threads setting is set to the correct amount (probably two)
http://uploader.polorix.net//files/1036/scene-output_panel.png

Please Search these forums before creating a new post. We have been around for over 10 years, and there is a lot of collective knowledge that is easily found using the Search function at the top of the page under the image. There is also the User Manual, and the Render page is located at http://wiki.blender.org/index.php/Manual/Rendering. On that very page you will find over 50 tips for render optimization. Enjoy!