Low 'n slow is the key. Minimum of 8 hours around 255 degrees F.

The night before I trim and dry my brisket and place it in a ziplock bag with a little orange juice or cola (it helps break down the meat) with ginger, garlic, salt & pepper

Next day about 2 hours before I plan to put the meat in my smoker I remove the meat from the bag and pat dry. Then I rub a spice blend I make, {sweet & hot paprikas (two kinds), salt, pepper, rosemary, ginger powder, onion powder, garlic powder & a little brown sugar}, into the meat and let absorb. I then use sesame oil and rub the meat all over and apply another dusting of the spice blend.
I usually smoke it for 8-10 hours depending the size of the brisket.