The best way is set and forget. Look at a temp/carb chart to determine what levels you want, set the co2 at that amount, and leave it. It should be ready in about a week.
Sometimes when I'm in a rush, I will force carb (30 psi, cold beer, shake and roll) for 4 min., vent, and use the set and forget to get it the rest of the way. This usually takes only a couple days.