I do:
- Strip case (remove panels, drive trays, etc).
- Arrange case fans (omitting any that might get in the way of motherboard installation, which was only the top rear slot on my Define R3).
- Install RAM, CPU and HSF on motherboard outside of case (omitting the fans on the HSF for now).
- Place standoffs, install motherboard.
- Wire front panel cables and some fan cables.
- Install PSU, wire as I see fit (including SATA cables to the soon to be filled drive bays, and necessary cables to soon to be installed GPU).
- Install HDD's, tweak wiring if necessary.
- Stick on CPU HSF fans.
- Install expansion cards.
- Replace case panels.