There are a thousand different ways to season a brisket, as a quick search on the internet will show you. Mustard rub, garlic powder, even baking soda.
When I was preparing to make my first brisket, I called up a few pitmasters and asked for their recipe. I expected them to respond with an overly elaborate recipe or complete secrecy, but shortly found that all suggestions led to the 50-50 pepper salt blend.
The secret is that the basics matter. The type of salt and pepper used is essential. Buy course kosher salt, since anything finer else will leave a brisket overly salty. For the pepper, freshly cracked black pepper is best. Invest in a spice grinder or use a coffee grinder dedicated to spices.
Mix the salt and pepper together. About a half a cup of salt-pepper works for a 12-14 lb brisket. Rub all over into every nook and cranny of the brisket. Do this when your brisket first comes out of the fridge, and let the rubbed brisket come to room temperature.
Smoke slow and low with the smoker of your choice. Enjoy!