4 things..
firstly thats onboard graphics(its on the processor).. so IF you did screw it up badly; the processor itself breaks (which means the computer itself becomes non-functional)
Secondly overclocking generally only slightly increases FPS (maybe a 25% gain if your lucky) So it might be worth overclocking if you are getting 20fps on the lowest settings in a particular game. (because it will bring it up to 25-30, which is a notable improvement). If you are receiving 40+fps, or dont have a specific game that needs that boost. Its hardly worth it
thirdly, IF you have a desktop, you should really consider a dedicated graphics card. for 80-100$ you can get something that preforms 10x better than what you have (and its fairly safe to install, though we probably want something low power..
4thly, if its a laptop (or upgrading isnt an option) make sure to follow the guides.. which will involve small increments, followed by stress test, followed by small increments (expect to spend 2-3 hours on this)
If its a desktop, and you want to upgrade, Ill need a bit more INFO to continue.. (because adding a physical card is actually quite easy, safer, and you will see tangible improvements)
Otherwise, I cant recommend it, unless you are willing to devote hours into reading up, and making it work.