WaterinHoleBrew is spot on. I will brine my shoulder overnight using molasses, sea salt, pepper, sliced lemons and oranges, apple cider vinegar and water. Mix and boil concoction then let cool. Once it is cooled put all in a large ziplock bag and place it in a cooler with ice overnight. In the morning, take it out, pat dry and get ready for your rub. You can use either a mustard or olive oil base. Apply your rub then set aside. Get your coals stoked and your wood chunks/logs chopped and ready.
I will smoke it fat side up (lots of discussion with this) for 3 hours then flipped it over. Total smoke time maybe 6-7 hours. Then I wrap it foil and stick it back in the smoker for another 2 hours. Your temp prior to wrapping should be at least 160deg. I find wrapping gets it through the stall. After this I prep my cooler by filling it with the hottest water you can get. Let the cooler sit with this hot water for about 20 minutes. Dump water and now your cooler is ready for the crutch. Take your wrapped shoulder and keep it all together and wrap in a towel. Place towel wrapped foil wrapped shoulder in your cooler to rest for 90 minutes.
After an hour mix up your sauce and then get ready to pull the most delicious shoulder your friends will ever taste. Here is my full recipe. http://www.myrecipes.com/recipe/smoked-pork-shoulder-232387/
Enjoy, have fun and keep experimenting!