The most important thing is to be calm, assertive and confident. Anger and shouting simply sends the dog a signal that that you are out of control. He will see this as weakness and will not follow you.
It's also important to be consistent. You can't let things slide one day and expect the dog to behave well the next day. If your dog is not behaving as you want, withdraw your attention.
One of your biggest tools in establishing and maintaining dominance is meal times. These provide a very natural and unmistakable signal to the dog when you are the one providing his food.
So don't squander this golden opportunity -- it comes naturally a couple of times every day, which is enough to establish and maintain you as the alpha. Always, without fail, make your dog do something to earn his food -- sit, stay, lie down, go to his crate, whatever you choose, but do something every feeding time.