My Tips:
Take the time to perform good cable management
Buy extra cable ties and [square shaped] cable anchors
Touch metal frame of case periodically to discharge static
Think about the thermal flow of your case (i.e., is the CPU heat exhausted well...is the GPU too close to XYZ...etc)
Install PSU last/Buy a modular PSU
Dont be rough with components/Dont force anything that doesnt fit well
Dont over torque screws
Clean your hands really well before touching parts
Test your system before closing up the side panel and getting it situated on the desk
Take your time, enjoy the building process
....
Every other month, take your case outside and airblast that baby out...keep a clean, dust free rig
Live long and prosper mate!