Here's a good "bike build" checklist I made a while back...
It's useful to glance over and make sure you're not forgetting anything.

Frame
Fork
Rear Wheel (rim, spokes, hub, nipples)
Front Wheel (rim, spokes, hub, nipples)
Headset
Headset spacers
Headset topcap
Star fangled nut
Stem
Handlebar
Seatpost clamp
Seatpost
Saddle
Tires
Rim tape
Tubes
Crank
Chainrings
Chainring bolts
Bottom Bracket
Chain
Cassette/Freewheel/Cog/Lockring
Pedals
Grips / Bar Tape
Bar Plugs
Water Bottle Cage
Brake Calipers
Brake Cables
Brake Levers
Cable Crimp Ends
Cable Ferrules