If you haven't see this brisket making video yet, check it out. Trimming technique at around 4 minutes is important, and then check out the wrapping and resting technique at 11 minutes thru the end, which is also really important in my opinion.
This video doesn't address how to pick a select a brisket from the store. I think it was Baby Back Maniac who did a video on the "jiggle test" where you grab a brisket and give it a little shake to see if it jiggles a bit or not. If it doesn't jiggle some, put it back. If it's got some good jiggle, it's probably OK. Any whole packer you buy will have some "hard" fat running around and between the point and brisket. Ones that don't jiggle much have more of this, once that jiggle don't have as much, and will be easier to trim and will cook up better. Between this selection technique and using Kosmo's wrapping and resting techniques, my briskets usually turn out pretty good.
Also, err on the side of getting the brisket on the hotter side. You gotta get up to 198 to 202 F and make sure you get a hot knife/butter kinda feel before you wrap it. If it doesn't feel like butter, even at 198F, let it keep cooking for another 15 to 20 and check again. "Done" is more of a feel than a temperature. Temperature just tells you when it's time to start feeling.
Finally, don't sweat the cook temperature too much on a brisket or pork butt, as long as you're temps are staying between 225 and 325 you're OK. Obviously you'll finish faster if you run hotter. If you run out of charcoal part way thru, don't stress, just finish it in your oven. Most of the smoke flavor is created in the first 3 hours of the cook.
Good Luck!
