When Installing it,
Remember - static-proof yourself - strap etc.
Consider whether its best to screw the board into the case first, then mount the CPU and memory you'll have to make that judgement yourself, there is never a single answer for that.
Make sure you have your power supply cabling planned out before putting in the motherboard.
Make sure you study the motherboard LED connector part of your manual carefully, if you haven't got an easy mobo solution for this fiddly bit.
Don't worry about any extra thermal compound, use what comes with your CPU.
Make sure you don't leave the plastic peel-off bit on the bottom of your heatsink (mate of mine actually did this, and we have never let him forget it).
Plan where your CPU fan will connect, and ensure that you can get to all the clamps, and fittings on your motherboard.
Powersupply to install before your motherboard.
Last bit of advice, prepare your location carefully for your assembly, tools, lighting, all ready and don't rush anything, or force anything. Aside from a 4-pin power connector very little requires any effort to plug in. And try not to drop any screws in the case
- apologies if all this is obvious to you, but thought it could be useful, as i have been putting PC's together about as long than some people here have been alive
