Dogs don’t speak English, and just because we might yell at our dog as we catch him in the middle of peeing on the floor and then rush him outside where he finishes it off… doesn’t mean we did an effective job at telling him that outside was where he was supposed to go. We are usually too focused on getting him NOT to go inside, instead of going outside.
The concepts of "pack" and "dominance" in relation to dog training originated in the 1940s and were popularized by the Monks of New Skete in the 1970s. The model is based on a theory that "dogs are wolves" and since wolves live in hierarchical packs where an alpha male rules over everyone else, then humans must dominate dogs in order to modify their behavior. However, recent studies have shown that wolves in the wild actually live in nuclear families where the father and mother are considered the pack leaders, and their offspring's status depends on their birth order which does not involve fighting to attain a higher rank, because the young wolves naturally follow their parents' lead.
Remember that training is an ongoing process. You will never be completely finished. It is important to keep working on obedience training throughout the life of your dog. People who learn a language at a young age but stop speaking that language may forget much of it as they grow older. The same goes for your dog: use it or lose it. Running through even the most basic tricks and commands will help them stay fresh in your dog's mind. Plus, it's a great way to spend time with your dog.
A training class is not there to train your dog. Its purpose is to teach you to train your dog so you will need to be committed to train your dog for short sessions (5 minutes) several times a day rather than just simply turn up for classes! This little bit of training everyday will be repaid with a lifetime of living with a well behaved dog. You will also learn to avoid problems before they begin as well as receive help to overcome any that you already have with your dog.