I take my time and make sure that everything is routed properly and accounted for. My average build takes about 3 hours, sometimes more.
I make sure I'm grounded and even wear surgical gloves when connecting. It's not just about shorting but fingerprints as well and the slight chance that some of your fingers oils may make it onto some connection and possibly cause a short. I know it sounds ridiculous but if you've ever dealt with Metal-halide bulbs you'll know you can't touch any part of them without gloves on for that exact reason.
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I tend to put the Rear Panel, PSU and Case Fans in first assuming they don't interfere with the placement of the Motherboard. This of course is case specific but I prefer to have that stuff in off the hop.
RAM is usually put in quite early because it's hard as h3ll to read what's printed on the Mobo. This of course depends on what CPU Heatsink/Fan Combo you're installing as you don't want the RAM in the way if you're screwing in a bracket to the front/back of your Mobo.
I then take care of the Mobo Heatsink/Fan Combo as depending on cooler, it's best to do this board out. Once that's been installed the Mobo is installed and all Power Connectors + relevant Cooling wiring is plugged in.
I then work toward drives and try to leave a space between drives that I know will be utilized more often for example OS and Primary Slave. Other drives that are utilized less frequently are stacked as they don't generate the heat the first 2 drives do.
All drives are then hooked into the Mobo and PSU.
Then I move onto Roms and hook them in.
All wiring is routed through the side of the case (in my case) or neatly tied together during this process.
Lastly comes the GPU's, additional fans, etc.
One thing I've noticed though is Mechanical Keyboards and Laser Mice don't seem to work at all during the setup process. Make sure you have some old shitty keyboard and IR Mouse during the setup process.
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I've seen numerous examples of builds that are powered to POST with the Mobo out and sitting on cardboard. This way if you have a problem you know about it before assembling everything.
It's a cool approach which I may try sometime but haven't up to this point. I can see how it would save you a tremendous amount of time especially if you have a faulty component.