Almost everyone teaches their dog to sit. That's great. It is the ultimate building block.
Many people almost intuitively know how to teach a sit.
But just as many people don't, and even those who do know may not understand why it is that what they're doing works.
How sit improves a dog behavior
As I said earlier, sit is the ultimate building block command.
Sit lays the groundwork for a sit-stay, and a sit-stay (tomorrow's tip) will come in handy in a variety of situations. Sit-stay also helps the dog learn patience, which is a valuable skill that transcends into almost all aspects of behavior.
How to teach a sit
This is an age-old method. People use it even when they don't know why it works. Teach it while your dog is a puppy and it is almost always a breeze for the puppy to pick up on.
I have met one adult shelter dog in my life who this doesn't work for. My guess is that somebody unknowingly used this method to teach a different behavior and now the dog doesn't associate it with sit.
OK, here it is:
1) Cup treat in hand. Put hand close to dog's nose. Wait until you are sure dog knows a treat is in your hand. You might want to make the treat partially visible.
2) Move your hand backward over the dog's nose and backwards so you wind up over the dog's eyes. What you're going for here is having the dog follow your hand with its eyes. You should find that, when your hand moves back-and-over the head to the point that the dog is having a hard time seeing it, he will automatically sit his butt down so that he can remain in view of the treat. This is the 'why' of why this old training method works like a charm — it's all about positioning the treat so the dog feels he has to sit to remain in view of it.
3) Give reward as soon as butt touches ground.
Keep doing this, saying 'Sit' while putting your treat hand over the dog's head.
Most dogs pick up on this one really quickly. Remember to keep using the hand signal until it seems like second nature, then, you can begin taking the hand signal out of the equation. If the dog does not respond to the verbal command, bring back out the hand command.
It is important that the hand and verbal commands are simultaneous — so, your hand moves back at the exact moment you say 'Sit.'
The dog will learn, over time, to associate the hand command with the verbal command. This will make it easier to start dropping the hand command all together.
Personally, though, I like the hand commands. Dogs almost always learn physical cues before verbal cues. My dog is eight and a half years old now. I can give him almost all his commands silently — with physical cues only — as well as entirely verbally (not giving any physical cues).
If you're looking for something to impress guests with, that'll do it. People think the dog and I share brainwaves or something, but that's not it at all. Just physical cues vs. verbal cues ...