A quick internet search will produce about a million different tips, tricks, and opinions on how to train and get better behavior from your dog. I'd wager that just about all of them have worked for someone, and for some dog, at some time. Rather than tell you, "This is how you teach a dog to... xyz," here are ten rules that should be ubiquitous across any training methodology:
1. Your dog needs a leader, if it can't find one, it will try to do the job itself
We put our dogs in a world that they can't possibly comprehend completely. We make them follow rules that don't make natural sense to them. The least we can do is be a good guide and mentor for them. This means we let them know who's in charge. Don't project negative feelings on me because of that last sentence just because you might have a crappy boss at work. When you know there is someone who knows what they are doing, is confident in their abilities, and is able to do the job in a leadership position, it sets you at ease. The same goes for your dog. If your dog does not find you to be a meaningful leader, it will assume that role itself because, well... somebody's gotta do it. But they'll make choices that make sense to them, which are incompatible with the world we have them live in. Out in the wild, it would make sense to guard your resources as a matter of survival. It would make sense to pee and poop wherever you want so long as it's not where you sleep or eat. It would make sense to run away from things that are a bit scary and to fight off things deemed a threat. None of these behaviors are compatible in our society. If you want your dog to conform, you better be ready to show them.
2. Make it exactly what you want, from the first repetition to the last
Practice doesn't make perfect. Perfect practice makes perfect. When placed in a situation where your choices are to make an exercise easier or lower your standards for performance, you should ALWAYS pick the former. Whether you are looking for a straight sit at the end of a recall or working through growling and lunging on walks, find the point where your dog can do it right and move forward from there only as quickly as they are able to maintain the standards of the exercise.
3. Fix one problem at a time
Small issues build up to bigger ones. Most problems on walks and anywhere else, are solved before you leave the house. If your dog can't sit still while you put their leash and collar on, they won't wait nicely at the door. If they can't wait nicely at the door, they won't walk nicely at the beginning of the walk. And if they can't walk as nicely during that first block, the rest of the walk won't be any better. Well, maybe after they're exhausted, the walk gets easier, but a TIRED dog and a TRAINED dog are not equal.
4. If it's not right at your side, it won't be right anywhere else
A dog that can't sit still by your side will never be able to walk nicely by your side. Reactivity, over excitement, aggression... the solution for EVERY. THING. starts with being able to do nothing. A dog that can't do nothing won't be able to do much. Tethering, benching, place, sit on the dog, crating... there are many exercises that can help teach a dog to find internal and external comfort, to self calm, and that they don't need to respond to every little thing that happens in front of them. Dogs, like people, need a clear mind to learn.
5. If it's not right on leash, it won't be right off leash
Does your dog jump on guests, get on the furniture, not come when called...? "Are they on leash?" is the first question I always ask.
Go to meet someone at the door, have the dog on leash, step on the leash so that there is enough slack that the leash won't get tight unless the dog's front feet come off the floor. Now open the door. The dog will be restricted from jumping. Wait until they stop trying and then ask for a sit. Allow your guest to pet them once (and only as long as) they are seated. Rinse and repeat.
Dog jumps on furniture. Dog doesn't listen when you tell them to get off. Just grab the end of the leash, and pull them off. Don't sling shot them across the room, just turn and walk with leash in hand and take the dog with you. Rinse and repeat.
Dog is in the back yard. You want to call them to come inside, and of course, they respond with "No." Attach a long line (15-20 foot leash) to the dog's collar and make sure you are holding the end of it before you call them. Give the leash a little tug and reel them in like a fish. Give them something really good (their favorite treat, a game of tug, whatever they like) . Rinse and repeat.
Here's where people go wrong: they only do this for a week or so. Do it (every. single. time.) until you don't need to actually use the leash (you never have to pull them, stop them, reel them, guide them), and then keep the leash on for 100% of the time it took to get to that point (so if it took 4 weeks to get to the point where you don't ever have to use leash pressure, keep the leash on for another 4 weeks). Dogs are natural gamblers. If they "win" one of these exchanges once, they'll continue to place bets. Make the result inevitable until you are sure your dog isn't calculating the odds.
6. Always have a recovery area
Another important thing I learned from Linda Kaim of Lionheart K9... Well, technically, I read about it in "The Koehler Method of Dog Training", but it didn't make quite as much sense until she illustrated the point for me. Dogs tie all kinds of feelings (which drive how they act) to a place where something happens. If you are working your dog through some kind of trouble spot, and they are stressing out or losing steam and enthusiasm, move to a different location and do something easy that you know they will get right to show them how easy it is to be successful. You don't need to get in your car and drive somewhere else. The first time Linda introduced this concept to me, I was working a dog on downs on a training table (pause table for you agility peeps) and the dog fought me a bunch, major resistance to any amount of leash pressure. She had me take the dog to another table less than 10 feet away and do a sit (something the dog 100% for sure knows and would respond to) and lavishly reward them for it. Went back to the first table and the dog melted into the down like buttah! This is seriously as close to magic as you'll ever come to in dog training.
7. Quit while you're ahead
Always end your sessions before you've completely exhausted the mental capacity of your dog. Sometimes we drill something so much that our dog loses steam and we take offense. Really, it's the dog that should be offended, that you're a jerk who can't recognize they did their best the last 50 times you asked for something and now they'd really like to take a nap. Particularly when your working on something that has been a real sticking point for your dog, when they nail it, stop. Don't "reward" that success by demanding 100 more of those things, whatever they are, in the same session.
8. You have to go back to go forward
Remember rule #5 way up there? That doesn't apply only to the house, or the back yard. It applies to ANY new situation you put your dog into. This is particularly important when people are moving into the proofing phase of training a behavior. So even if your dog is 100% perfectly reliable off leash in your yard, when you go to a new place or work around new stimuli, start on leash and make sure everything is just right before moving forward.
9. Under stress, animals go back to what is most familiar
When a dog is aroused in any way they typically revert to whatever behavior is instinctual or the strongest habit. It does us no good to only train in relaxing environments, or by avoiding things that typically trigger them. We have to work through those situations. The only way to teach a dog to cope... is to make them cope. This doesn't mean throwing them into the deep end, but it does mean that you need to train behaviors to the point of habit, under the same circumstances where they would usually fall apart (once foundation work has been completed, and by working up to those situations methodically) if you want to really resolve issues. If you still have any second thoughts about how your dog is going to act in a situation, you have more work to do.
10. Do not give a command you can't (or won't) reinforce
Going back to #5 again, where I said dogs are gamblers. People go through 6 weeks of a group class and think they're done. Their dog "knows" sit, and stay, so they use those words while they sit on the couch at the end of the day. The dog blows them off, but they are tired, so they let it slide. Congratulations! You just made 10 times more work for yourself.
Keep the dog on leash so it's easy to follow through. And think before you tell your dog to do something. If you aren't going to be willing and/or able to follow through, you'd be better served by crating them (managing their behavior by limiting their options and not allowing the opportunity for them to do something wrong).
And a bonus...
11. Always train, never test
Tests are fine for kids in school. Not for dogs. Whenever you are with your dog, get it in your mind that you are not testing them to see if they are going to do the right thing or the wrong thing. You are, instead, going to give advice and guidance... as much as necessary, but as little as possible... always. This is an important thing to get in your head. I've said this in front of group classes before and literally seen an immediate change, a softening in handling, a release of tension, and an overall more understanding attitude from clients. The actual actions (leash pressure, corrections, praise, everything) don't actually change. But the attitude and the vibe the person is giving off makes a major difference to the dog.