@yi_orange: Check out r/buildapc on Reddit or tomshardware.com if you want to get a lot of knowledgeable information. If you post your plight to build a PC, then I bet you'll get a few decent builds. Like others have said, pcpartpicker.com is a great resource.
logicalincrements.com is a great place if you want to skip the development step and just find a build that fits your budget.
My personal advice is to ignore overclocking unless you really are into it. The premium isn't worth the performance gain in gaming.
For this price range a i5-4590 CPU should work well with a 770 or 280x GPU (depending on manufacturer preference). Storage wise, a SSD with a HDD for games. Be sure to pick up a second HDD if recording gameplay(don't want to skip any frames!). A common mistake is to overspend on the PSU. The simple solution is to buy a quality brand (Corsair, Cooler Master to name two) with the minimum required wattage for the GPU. Wrapping up, 8GB of 1600 MHz RAM should be able to be bought for ~$70. You do not need more than 8GB unless you will be doing: virtual machines, CAD or professional video/photo editing.
Hope this helps and good luck :D!