If this is your first brisket then I would do the following:
1) Night before rub the brisket with worshteshire-rire-y, worshty... yeat that sauce! then put your rub on the brisket. Keep it simple - salt, pepper, garlic powder, and paprika work well. Wrap it in plastic wrap and let it get happy.
2) Fire up your smoker, bring it up to 210-220° and toss in your brisket. Place a foil pan with 1 bottle of good beer in it under the brisket.
... now comes the hard part!
3) Leave it alone! Don't peak, don't poke, just leave it be untill the internal temp. gets to 165°.
4) At 165°'ish take the brisket and put it in the pan with the drippings and cover it tightly with foil.
.... 2nd hard part - you guessed it, leave it alone!
5) Wait for the internal temp. to get between 190° and 205° (190 for slicing 205 for pulled/shredded).
.... Don't try to rush it! Don't turn up the temp on the smoker! Don't pull it early!
6) Pull it out of the smoker, double wrap it in heavy foil, then place it in a dry towel lined cooler and cover it with more towels..... and the really hard part - wait for 1 hr.!
7) Open it up and enjoy the best dang brisket you ever had!
Suggestion: while the brisket is resting take the juices from the pan and the juices from the foil and put them in a small container and toss it in the freezer till the fat sets up. Pull the fat off and re-heat the juices to spoon over the brisket as a finishing sauce.