Okay first off i use a brinkman smoker with a side smoke box as ive found this to be the best smoker.
Prior to dry rubbing rinse well in cool water and pat dry with a towel.

INGREDIENTS for dry rub:
Season Salt
Pepper
Garlic Powder
Paprika
Ground Cumin
Chili Powder
Ancho Chile Powder
Brown Sugar

Season it nice and good, wrap it in high quality plastic wrap(costco has it)and let it sit for atleast 1 day in the fridge. Smoke it on medium heat(FAT SIDE UP) about 1hr15min per pound. Once its reached a internal temp of 180ish remove from the smoker and wrap it again in plastic wrap and aluminum foil let it sit out for about 1-2 hours and it ready