Have your dog sit on your left. As you say stand, pull his leash forward with your right hand and move your left foot forward like you are going to start heeling. Say good boy! as soon as he stands up.
Here is another way to have your dog stand. Have him start in a sit and bend down to him. As you say stand, pull his leash forward just a little while you push your entire left arm backward from just behind his front legs. Your pushing backward should make him stand up. Good boy!
In the show ring, your dog is required to stand while being touched all over for inspection. Once your dog stands on command, have a family member touch the dog so he can get use to it. The person’s hand should start by going slowly toward the dog’s face and stopping briefly in front of the nose so the dog can smell the hand. The person then rubs his hands down the dog’s sides, down each leg, down the tail, and then goes back up to pet the dog’s head. (In the ring, the judge would also open the lips to see the dog’s teeth.)
Information obtained from Lace to Leather.