Rescued dogs offer a variety of training challenges, depending on their previous experiences. However, you can't ask your rescue dog what those experiences were, so you just have to move forward with training the dog you are given, tackling challenges as you encounter them.
Training a Focus
The first thing you should train your rescue dog to do is turn to you for help when he isn't sure how to react. This can help reduce fear and reactivity, which many rescue dogs exhibit at some point.
To do this, teach your dog to look at you as his default behavior. Since most default behaviors (barking, lunging) are undesirable, this teaches your dog a command that he can fall back on when he isn't sure how to behave.
For the first month you have the dog, handfeed him all his meals. Use this opportunity to teach the focus command. Say your dog's name. If he looks at you, reward with a handful of food. If he doesn't, move the food up to your eyes as a lure. Praise before you give the food.
After a few repetitions, don't use the lure any longer. Wait for your dog to get it right. Then, you can start making it harder by practicing in more distracting environments, such as the yard, parks or daily walks.
Teach House Rules
For the first few weeks, your dog won't know how to behave in your home. He may have never even lived in a home. Thus, he hasn't earned house freedom. When you aren't home, keep your dog confined in an x-pen or small area of the house. Don't live him alone in the back yard because that could lead to digging, barking or trying to escape.
Then, your dog will only have house freedom when you are home, so you can teach him which objects he's allowed to chew on, which locations he's allowed to relieve himself and when he's allowed to bark or get on the furniture. Without your guidance, you can't expect him to make the right decisions.
Set Boundaries
Many rescue dogs became so because they escaped a yard and didn't return home. This means that before they know you, they might try to escape your yard as well. For the first few weeks, don't allow your dog outside alone for long periods of time.
In conjunction, teach your dog a boundary at each door and gate, so he learns that he can only cross certain boundaries with permission. To do this, for example, at the front door, put your dog on leash and step out the front door. Say "wait."
If your dog tries to bolt past, don't pull on the leash. Instead, use your body to block the doorway. Step into the dog to move him back. Repeat your command and step back again. Repeat until your dog doesn't try to make a move forward. Then, praise and give a release command, such as "go free," "OK" or "release."
Before he walks through any of the boundaries, even for a walk, he needs to hear that release word. Gradually build up walking farther or making him wait longer. Once he can do it well, you can start practicing without a leash.
Rescue dogs make wonderful pets, but sometimes, they require a little extra training. If you stay positive and patient, however, these dogs will be eager to learn and adapt to your lifestyle easily.