The following are exercises that I recommend every dog owner employ to some degree, but which I highly encourage owners who are rehabilitating aggressive or anxious dogs to follow closely. These steps, in addition to regular obedience training and clear discipline, work to reconstruct the relationship between owner and dog, and place you as the owner in a space of healthy respect; which will in turn create a stronger bond between you and your canine companion!
*please consult a professional if you are dealing with severe behavioral issues. The below must be established in conjunction with a solid training plan and are not a quick fix*
1. No elevation -- Do not allow your dog onto furniture or onto your bed. In a natural pack of dogs, the best sleeping place is reserved for the alpha. This is a luxury, and if you are in a space of dealing with aggression or any other serious behavioral issues, your dog has certainly not earned it. This may be something that lasts a month, or for the remainder of your dog's life. By allowing them this privilege, we can inadvertently be stroking their egos and often times over-compensating on the amount of affection they receive.
2. Crossing thresholds -- Make it a point to have your dog wait patiently before entering/exiting different areas (crate, doorways, car, etc.). Make them wait to receive rewards such as meals, treats, toys and playtime. You can do this by using obedience commands and providing consequences when those commands are not followed, or simply using your body as a boundary for crossing the threshold before you give permission. Being consistent in this area will create the habit of your dog looking to you for permission instead of doing or taking things on their terms.
3. Structured meals -- Do not free feed (leave food out so they can eat whenever they want). This is a bad idea for a number of reasons, including that it is simply not healthy, but for these purposes we want to make it clear that you as the owner control this valuable resource of food, and you want to make your dog "work" for their meals. As you prepare your dog's food, make sure that they are remaining calm during the entire process and not going crazy with anticipation. Only a calm, patient demeanor should be awarded with food. If they do start getting excited, pause the process and do not continue until they've begun to calm again. This may take several attempts. If helpful, you can use obedience commands to cultivate calmness, but remember; just because a dog is in a down command does not mean they are calm.
4. Affection on your terms -- We don't even realize it most times, but you would be surprised at exactly how often your dog is "telling" you to give them affection. Some examples of this are snuggling up to you on the couch, coming over to lay next to you when you are seated, leaning on you, pawing, resting their head on your arm or hand, nudging with their nose, etc. These are exactly the times that you should not be giving your dog affection/praise. You are the leader. You decide when it is time for them to receive attention and when not to. When you dog does one of the above, give a firm, "no" and ignore the behavior, or give them an obedience command to do instead. The best time to provide affection is when you've invited the dog to receive it.
5. Playtime on your terms -- Similarly to affection, you will begin to notice how often your dog decides when playtime starts and ends. The easiest way to accomplish this exercise is by keeping toys out of reach until playtime. You pull a toy out when you are ready to play with your dog and then end the game BEFORE your dog gets completely disinterested in you or the toy. This will accomplish several things; first, your dog will recognize that you control yet another resource - their toys; second, they'll begin to value playtime more as their toys are no longer always available to them; third, playtime will be a valuable activity that always involves their owners; and fourth, you will be positioning yourself as leader by not allowing them to make the decision of when this activity takes place.
There you go! You're on your way to a better relationship with your dog!