Want to overclock graphic card and processor

Hello everybody,
It seems this is the best forum for overclocking stuff. I've read threads and threads in this forum, really helpful indeed.

However, I have old computer and I'm not planning on getting the new one because I'm just using my computer to play old sql games such as CoD2, C&C Generals, etc.. I'm not really into new games, to much requirements to follow eh ..

Well,
I have Intel Core 2 Duo E6300 1.86Ghz with Intel cooler on ASUS P5LD2 SE motherboard,
1.5GB RAM Memory DDR2
and NVidia GeForce 7900 GS.

I'd like to overclock graphics and processor but not to much. I'm new into this and asking for ur help. Don't want to screw things up.

Thanks!