Overclocking i5 on MSI Z77A-GD65

I built my computer last year in November, so I'm pretty new to the PC world and I just want to overclock my i5 2500k. I know I have to go to the bios and tweak some things out but I don't know how far I should push it and such.

Here are my specs:

i5 2500K 3.3GHz

MSI Z77A-GD65 Motherboard

Corsair H100 Liquid CPU Cooler

16Gbs G. Skill DDR3 Ripjaws 1600MHz

2 EVGA GeForce GTX 660Ti SC+78MHz GPU Clock 2GB DDR5 (Should I upgrade to a 670 or 680 or am I ok?)

Corsair G. Force 60GB SSD 

Western Digital Caviar Black 1TB HDD

Corsair HX 1050 PSU

Corsair 800D

LG Blu-Ray

Lamptron FC6 4 Way Fan Controller

LG Flatron E2742 1920x1080 Monitor

It's a delicate balance and it varies from chip to chip.

If you want, you can try my settings. I have most power saving features enabled, though I disabled Turbo.

I have mine running at 4.5GHz: 100MHz base clock with a 45 multiplier running at 1.325v. I have a Xigmatek Dark Knight cooler (first revision), and my temps get up to 68c.

I use Prime95 in-place large FFT for short term stability testing (20-30min), and small FFT for long term stability testing. I use CoreTemp to monitor temps.

I keep fiddling with the settings and testing with short stability tests until I find a setting I like with temperatures that are acceptable. Once I have a setting I think will work, I test with a long-term test, which I usually run for 12-36 hours. According to Prime95's documentation, most CPU errors occure after 16 hours of testing, so 24 hour is recommended.