A couple tips.
Since this is going to be a gaming rig, make sure to get a nice case with nice airflow, it doesn't have to be the best, but something nice.
DON'T SKIP ON THE POWER SUPPLY. It is for some reason always just picked quickly, as it for some strange reason, seems not important.(Even I picked out a cheap one, and realized what I done and got a better one for my next build)
Put your CPU along with fan and heatsink, along with RAM in before you put the motherboard in your case.
Cable management helps you in three MAJOR ways.
1. Makes your case look sexy if you have a side panel window
2. Helps with airflow, the air doesn't have to pass through and get disrupted by wires.
3. Makes future upgrades that much easier, as you don't have to get past a mountain of cables to drop something in.
Static electricity hates you, use an anti-static wrist strap, but you don't necessarily have to. If you are smart, don't work on carpet, and take off your socks, and hold you metal case while working you'll be fine.
If you're forcing something in, it's probably not supposed to go in that way!
However, there is one exception, and that is RAM, you can be surprised how hard it is to put that in!
A 200 mm fan will cool the same as a 80 mm fan and do it much quieter, why?
A 200 mm sucks more air, so it has to spin at a slower RPM=Less noise then a 80 mm fan.
Try to find a case with fan filters for the fans, so it doesn't get dusty inside, if you can't find one for the right price, make sure to clean out regularly.
A modular power supply is always helpful, as you can take out the wires you don't need, however with planning and some patience, and "Standard" power supply will look just as good.
If you are using IDE cables, but you will probably want to go for SATA (SATA=Faster, MUCH MUCH smaller wires, makes case look better)
But if you have to use IDE, try to find nice wire rounded cables, it will make that much difference.
If you are putting wires under your motherboard to conceal them, don't go around rubbing them on the motherboard and being forceful, it can and eventually will break your motherboard
Hope this all helped, if any questions, feel free to ask we'll gladly help out!