ohh, i did not notice that you have a 750Ti. my suggestion, sure, oc, but don't go overboard. oc just to learn how to do it.
because your gpu will be a bottleneck, so even if you oc to the maximum of what your hardware can handle, it will still be not that fast in most games.
so if you want to learn, read read read and try it out. but do not expect much in games until you upgrade your gpu ok?
also, it takes patience to oc as you have to test and test and test.
first thing to know, check the max safe voltage and temp of your components. you don't want to fry your components.
take it slow, don't jump directly to 4.5ghz esp since you are new.
watch your voltage and temp