Overclocking a Raspberry PiIt's very simple to overclock a Raspberry Pi, i.e make the processor run faster. There are probably many settings you can alter, but all I do is edit /boot/config.txt:
$ sudo vi /boot/config.txt
And edit the line
Uncomment arm_freq if it is commented (if the line begins with # or !, remove the # or the !)
Save the file, and reboot.
I have both my Raspberry Pis running with arm_freq=1024
They are both stable, and don't overheat. One is in a case which does have venting for heat. The other just sits on top of my tv with no case or venting.
I can't vouch for your Pi, and don't come running to me if yours doesn't work. I'm simply saying here how I overclock mine. Try small steps at a time until you're happy it's stable. E.g. try 800 then 900, etc.
Be aware, any overclocking can brick your machine, overheat it, and/or invalidate your warranty. As far as I'm aware, you can overclock a Pi to 1024 without invalidating the warranty - but please don't quote me on that. It's just something I've read. Both mine are on 1024 and working fine, but yours might not be able to.