greedy09

This is a good guide, I used this when I was overclocking my CPU. 
http://lifehacker.com/a-beginners-introduction-to-overclocking-your-intel-pr-5580998

Start by checking out Linus' video on Haswell overclocking

For the CPU I recommend following this guide:

For stress testing I would recommend you to use the Intel Extreme Tuning Utility
Only the overclocking is done in the BIOS. The stress testing is done in the OS:
 
For the GPU the steps are quite simple
Download and install either MSi Afterburner, Asus GPU Tweak or EVGA Precision X Increase the core clock with 10-20MHz Stress test using Unigin Heaven or a graphics heavy game If stable, repeat If unstable, raise the core voltage with 5mV Repeat until you hit 90C on the GPU You can also overclock the memory, but it doesn't have the biggest impact on performance
Raise the memory clock with 25-50MHz Stress test (See step two of GPU overclocking) If stable, repeat If unstable, scale back to last stable setting. 

Everything is done in the bios, then download prime95 for stress test. Watch Linus' video.