- vise held down with tnut etc hardware. A good vise is KURT with better than 6" opening preferred.
- set of different height parallels 1/8 inch thick for small parts and 1/4 inch for the larger ones.
- Dial Calipers
- end mills: center cutting 2 or 4 flute.
- collet system to hold end mills. Spring collets like the ER40 on larger mills are nice.
- DRO (digital readout) is a nice feature to have but not necessary.
- drill chuck and drills
- rubber mallet
Make sure your mill is trammed 
Place part in vise on top of parallels and tighten vise. Use rubber mallet to pound down the part and tighten vise more parallels should not move if seated well.
Making a rectangle object Best to square up the sides first. Place part in vise cut one side, flip part over and cut other side. Lay part flat using the two fresh cut sides in the vise and use the side of the cutter to cut 3rd side. Flip part over and cut 4th side with the side of the cutter. Now sides are square and the part can be placed at correct height to cut the faces of the part. Flip part over and cut last face.