1. Pitch enough healthy, viable yeast. (check out Mr. Malty or another yeast calculator for this)
2. Pitch into cold wort. (at least 48-50F)
3. Depending on how you want to run your fermentation schedule, I have had good results with this....
Ferment the beer at 48-50F until the krausen starts to drop back into the beer.
Ramp the temps up a few degrees/day (I usually go with 4F) until you hit 65-68F. Let it sit for around 1
week at these temps for a good thorough diacetyl rest. This is just how I do it, and I am sure others will
chime in with their experiences too.