I don't know if there is a best way. I have had dry rubbed, wet rubbed, marinated in a bag, sauced, unsauced, cooked in an oven, on top of a stove, slow smoked and cooked on a camp fire and most of them were pretty good.
There are dozens of commercial dry rubs on the market. If you look at the ingredients of them you will see the similarities they all have in common. Keeping the brisket moist during cooking is paramount and people have their opinions on what to use. Some use a vinegar base basting sauce, some use fruit juices and some even use plain water. Whatever you decide to use, use it often and try to keep as much heat inside as possible. Every time you open the oven door or smoker lid you add cooking time.
I am cooking a small brisket on a Big Green Egg tomorrow. Tonight I will rub the brisket down with a couple tbsp yellow mustard then add a commercial dry rub rubbing it into the meat real good before wrapping in double foil, shiny side in, and refrigerating overnight. Tomorrow morning i will build a fire up to around 250F and start adding wood for smoke. I have oak, pecan, hickory and apple to choose from so I will probably use 1/3 mix of oak, pecan and hickory. When meat gets to about 170 it should have a nice smoke ring on it. Wrap the brisket back in the double foil, add a good quarter cup of liquid (water, wine, fruit juice, beer, beef or vegetable stock) and put it back on the pit till it gets to 195-200F then remove from the pit, wrap in a couple of towels and put it in an empty ice chest for an hour to rest.
Now you can unwrap the meat and cut it across the grain. This may not be the best but it should be a great brisket.
My secret liquid elixir for brisket is beef bullion in beer with a dash of Worcestershire sauce and a clove of minced garlic.