I agree totally with what landarc said earleir in this thread. I have done brisket five tiems now and I kept it real simple at the beginning and added something on the next cook and then something else on the next and so on. I looked at it from the point of view that WHEN something goes wrong the less variables I had to sort through the easier it wold be for my to figure out what went wrong.
For example when I did my first one I used a simple salt and pepper rub and ran my pit at 275. The next time I changed the rub, still ran it at 275. The next time I added an injection, used the same rub and didn't worry abut the pit temp too much and made sure it probed like butter. My last cook was a disaster from a temperature control point of view but my wife said it was the best tasting brisket I have done to date.
Just keep it simple and slowly add levels of complexity as you gain experience. I am so far from being anything approaching an expert, but I do know what works for me.
Good luck and don't forget to have fun with this.
Weber Performer w/smokenator
When all else fails just ask yourself, WWGALD???