First of all, use some time today to look up what breed, size, energy level, temperament dog would suit you.
I found this site very helpful:
http://www.dogbreedinfo.com/search.htmSecondly, be aware that a GROWN dog may or may not have some bad habits, zero training, etc.
I personally prefer to start with puppies I can train, but many others have found a grown dog that works for them.
This might help once you get to the shelter:
1. As you enter the shelter, get a reading on the attitude of staff and volunteers. Are you greeted warmly and treated well? If you are asked to fill out a questionnaire, are the interviewers genuinely interested in who you are and helping you find the right dog, or are you grilled like a criminal? Any concerns about your answers should be used to help educate, not condemn you. If you feel like you are getting the thumbscrews and third-degree, leave. It would be almost impossible to concentrate on your task in an environment like this.
2. When you enter the kennels, make a quick pass through without stopping to schmooze the dogs. Pen and paper in hand, make note of any dogs that stand out for you. Ideally, you might find four or five who do.
3. On your second pass-through, stop and visit with each of the dogs you noted. Put your hand up to the kennel wire or bars. The dog should readily come up to visit you and sniff your hand. Remember, these dogs are socially deprived, and should be seeking your attention. When a candidate sniffs your hand, tell him he's a good dog, and move your hand back and forth, slowly, several times, about five inches each way. A social dog will follow your hand. Remember, you want a social dog a well-socialized, outgoing, and friendly dog is the least liable to be aggressive. If the dog jumps at your faces, barks at you, lunges or, alternatively clings to or retreats to the back of the kennel, cross him off your list and move on to the next dog.
4. When you have identified the dogs on your list who are very social, take them out of their kennels one at a time, to a quiet room if possible. (Not all shelters can provide this luxury. Do the best you can find a relatively quiet corner somewhere.) Stand with the dog for five minutes, and totally ignore him. The dog should look at you in a warm way, and try to worm his way into your affections leaning on you, nudging, licking, trying to cuddle. Jumping up is okay if it is done as attention-seeking, not in an attempt to bowl you off your feet as he bounces away from you. If an employee is with you and the dog is seeking attention from the employee, that's okay it just means the dog has already formed a bond with that person. If in five minutes the dog shows little or no interest in you or in other humans who are with you, put him back. He is not a good candidate.
5. If he is very social, pet him slowly and gently down his back. He should stand still and enjoy this, or lean into you, seeking more contact. If he shakes you off after you've touched him ('Yuck, people cooties!) or moves or lunges away from your touch, he's telling you he doesn't like being petted, or being around you. This dog is at risk for being aggressive anytime people touch him in a way that offends him. Put him back.
6. If he passes the petting test, ask a shelter staff member if you can feed him a meal a small bowl of kibble, or a handful of biscuits that you brought with you. You want to test him for resource guarding another behavior that puts him at high risk for biting. Put a bowl of food or pile of treats on the floor, enough that it will take him about 45 seconds to finish it. Now (BE CAREFUL!) talk to him, then pet him gently on the back. (Do not try to take the food away!) You want him to wag his tail, wag his tail harder, or even stop and look at you as if to say, 'Hi! I'm eating right now, I'll be back with you shortly. He may even stop eating and prefer to be with you. However, if he stiffens, blocks you with his body, glares at you, lowers his head into the dish, growls, or tries to move the food away from you, he is a resource guarder, and not a good adoption choice.
7. If he passes the first food test, up the ante. Ask the shelter staff if you can give him a chew hoof, pig ear, rawhide, or some other very valuable object. Again, you want to see if he is cooperative or competitive with this resource. Slowly move toward him and look for any of the guarding signs described in the previous step. If you see them, stop the test. If not, slowly reach for the object from a distance of at least two feet, then jerk your hand back. Repeat this step three times. You are looking for a dog who is relaxed about your approach. If you see any signs of guarding, don't adopt. Have the staff person retrieve the valuable object and put the dog away.
8. If the dog is still with you, your next step is to pet him all over. He should actively enjoy being petted, perhaps wag his tail, even lick you. He should not mouth you, even gently. If he does, put him away. Mouthiness, even done gently, is a sign of resistance, and may escalate to a bite if someone, such as a child, ignores the sign and keeps on petting or touching.
9. Now take out a toy (that you brought with you for this purpose, or one that the shelter provides, if they prefer) and see if he will play some sort of game with you: fetch, tug-o-war, or chase. Play the game for three to four minutes enough to get him excited and aroused. Then abruptly stop the play, and put the toy up, preferably on a shelf where he can see it. Take note of how long it takes him to disengage from playing and return to you to settle and socialize, perhaps sit or lie down next to you. Ideally, he will do this within two minutes. If he is still aroused after five minutes, put him away. This is the kind of energy level that the average dog household is not equipped to deal with. (If, on the other hand, you are looking for the next World Frisbee or Agility Champion, he might be a candidate.)
10. Take the dog for a walk on leash, outside if possible. Don't worry if he pulls, or is very distracted these are behaviors that are normal for shelter dogs, and can be retrained. Do watch for aggressive behavior toward other dogs or people while he is on leash. If you see any, put him away and cross him off your list.
11. If this dog is still on your list when your walk is done, have a staff person put him back in his kennel, then watch him as other strangers pass by, especially children, big men, and anyone who moves or dresses oddly. Avoid a dog who barks or lunges at anyone who walks by this is a sign of inadequate socialization. If your dog will be around children, look for a dog who wants to greet passing children first. A dog who will live with children must worship little humans, not just tolerate them.
12. If you still have one or more candidates in the running, ask the shelter staff if you can put them on temporary hold while you make arrangements to return with your kids and spouse (if you have them) and trainer. You may also want to bring your current dog, if you have one, so your trainer can help with the first introduction. Shelter staff may tell you that they can't put a dog on hold, because if someone else wants to adopt in the meantime and you don't return for some reason, he might miss out on his best chance for a home. This is reasonable. However, they should be willing to note that you are interested on the dog's paperwork, and give you a reasonable amount of time to return, so the dog isn't selected for euthanasia before you can get back with your crew in tow. When you do return, your trainer will be able to help you make an educated final decision about which of the dogs on your short list is the best choice for a long relationship with your family.
Good luck!!!! Let us know if you find a good match for you.