Something else - it helps to get on a dog's mental level when training. Too often, people assume dogs have the same logic and reasoning that humans do. They do not - they operate on a very limited subset mentally of action/reward/punishment. They also have extremely short memories. If you come home and Fluffy peed on the floor two hours before, yelling at her now won't do any good, she will just associate you as being angry for whatever action she is currently doing.

Also, remember that a dog's first priority is almost always to have fun. Anytime you are training and you can make it into a game for them, they will learn that much quicker.

Finally, in my opinion, the most important thing is establishing that pack order and just getting the dog used to following your instructions. When we first rescued our two, I did teach them the basics of sit, stay, etc - but with an emphasis on following commands in general rather than mastering one in particular. Since then, I've done next to no training at all with them because they are conditioned to do what they are told regardless of what it is. They learn new things now at an incredible rate - and if your doggie loves and respects you, they will always go way out of their way to please you!