Obedience Tricks
Sit: If you are using the method of reward training, tricks might be a little easier taught. Always make sure you use a stern voice when training a dog, let him know who's boss, I believe, however that harsh training is cruel, and is not needed in both cases.
1. Get the dog into a standing postion, hold on to his collor, and start by gently pushing down his hind quarters, while saying the command "sit", if he sits praise him. Continue this until he can learn sit on command.
2. Another way to train "sit", this is probably more easy on the dog, again have him in a standing postion, instead of pushing his hind quarters down, push in on the back of his legs, just above the hock, this should work, and is especially easy if it is a puppy. Continue to do this until he learns it on command.
3. Another easy way to try this is by hold a treat, or toy slightly above his nose while saying the command sit. Usually dogs tend to sit when they have things held above their noses. But don't hold it too high or he will try to jump up for it. Once he does it, praise, and continue this until he learns on command.
Stay: Once your dog has learned the sit command, it's time to move on to this.
Get the dog to sit, start commanding Stay, then slowly walking away from your dog, only a short distance at first. If the dog follows you, or gets up, just do it again, it may help to use the familer "stop" hand signal.
If the dog stays, walk back to him and praise him.
Continue this until it is learned on command.
Remember: If your dog stayed on command, always go to him and then praise him, never let him come to you first, or he might confuse this command with "come".
Come: Your dog can be in any postion for this command, but it may be easiest to start with a standing postion. Once you have your dog in the postion you like, using your "training voice" command come, it is a good idea to add the name of the dog you're training, so that he knows when you command come or call his name, he knows that you want him to come to you. So instead of simply commanding come, you should be commanding (an example) "Chewie come". When the dog responds and comes to you, always praise him.
Remember: When training come, it is good to practice this outside too, so your dog dosen't simply think "come"  means inside business only.
Also if you leave your dog outside unsupervised, and you call him to come, and he dosen't answer, but for example, you see him over at your neighbors yard, first just try calling him a few more times, if he responds, and comes to you, DO NOT punish him for being over there, for he will simply think you are punishing him for coming to you. That is probably the #1 mistake people make when training their dogs this.
Lay Down: 1. Have your dog in the sit postion, you could start by having a lure, like a treat or toy, to get him to consentrate better. Using the reward postion your hand  his muzzle, and slowly move it down to the floor, by having the reward, move to the floor he should get the idea of what your trying to make him do. Don't forget to give the command word. Once he's done it praise him.
2. Put a hand on his back, just by his shoulder blades (above his front legs), and gently pull out his front legs to get him in the Lay postion, reward him once done.
Remember: It may be a good idea to have the dog on a slipperey surface (like a wood floor or such) It may be easier for him to "slide" into the postion.
If you are using version 2, make sure you very gently pull his legs down, so as to not hurt him.
Training a dog should always start with Obedience Training, it is best to start this when just a puppy, but you can teach an old dog new tricks too. In any case Obedience training will help to better your dogs behaviour, and will alow you to have control of your dog when needed. And in some cases could even save her life one day. Once you pass the obedience training, other fun tricks will be easier to teach, and you will have your dogs full attention.
I believe in the method of "reward training" for it is not hard on the dog and in my experiece one seems to get better results.
Whether your using treats, toys or affection, your dog should soon come to relise that a little bit of work for that is defenitly woth it!