Hello,
I am Andrew and I had the same questions. The first thing to look for is the temperatures your computer is running at in the various parts. most important being the motherboard cpu and videocard. You can look up monitoring programs on the internet. I use Corsair Link.
This is the download link if you want to download it:
http://www.corsair.com/en-us/support/downloads
If you look up what is a good temp for each component to be at and they seem on the higher end I would consider investing in fans to lower the temps by moving the hot air out.
These are the things I look for in a good fan:
1. Noise (lower db or decibels is better)
2. CFM or cubic feet per minute (higher cfm is better)
If you don't know what is a good amount of noise 120 db is the threshold for pain 60 db is about the normal talking voice volume 20 to 25 is a good fan volume. As for the CFM I would look for around 60 plus cfms for a 120mm fan and less for an 80mm fan which are pretty much the most common sizes I see in computer cases these days. double check that it fits your case before purchasing. The last thing you want is the wrong size fan you drop 20 bucks on.
Here is a fan I think is good at 120mm:
http://www.newegg.com/Product/Product.aspx?Item=N82E16835233098
Here are some fans I think are good at 80mm:
http://www.newegg.com/Product/ProductList.aspx?Submit=ENE&N=100007998%20600035580%20600035662%20600035651&IsNodeId=1&name=60-65%20CFM
double check the cases specs to see what fan size your case takes and make sure you have enough clearance to fit it some higher end fans can get thick. Also, stay away from server fans like delta it will make your head pop from the noise.