help! i5 4670K overclocking

You can try and go for 1.35v vcore, can probably get around 4.5ghz out of that. Just set the multiplier to 45x and it will be 4.5ghz. If its not stable reduce to 44, if it is stable you can go one step up.
For a beginner I don't think you should go much higher than 1.38v max, and try to keep temps under 80c.

Well if you want to soak up all the information people have gained todate, then start here

http://www.overclock.net/t/1411077/haswell-overclocking-guide-with-statistics

Then post your specific questions here or there. The above advise may work, it's really not rocket-science at the end of the day but if it doesn't then there are other things you can play with.