There are some basic things that apply to any training that you want to do. Remember these things and all training will be more successful.
Positivity- all living things repeat behaviour that gets them positive rewards.
Patience. Very important, with patience comes great rewards.
Use a mixture of high and low value treats
Begin any training in a low distraction environment and just the two of you. Dogs struggle to train with distractions. Only add distractions when they become proficient without them.
Pick your spot to train and stick with that spot until they “get it” and then move to another spot until they “get it” there too. Keep moving spots until they “get it” in many different situation and locations.
Invent fun games to play with your dog, so you are a fun person to be with.
Set them up to win by teaching in small, easy stages. Failing is demoralising and you may find they get upset if they fail too much, so always pop something you know they find very easy in a training session to make them feel good.
Be 95% sure your dog can do the thing you are asking, otherwise you are setting them up to fail. Drop your goals to something you are 95% sure they can do.
Only say the command once. If it is ignored, do not just keep repeating it, it will lose any value.
Make them earn their rewards. Only give treats or attention for positive behaviour.
Train for short periods at regular intervals.
Only give the command if you are certain the dog can not access the reward if they ignore your command (remember rewards are not just treats, the reward can be getting to another dog or jumping up at someone and getting a stroke).
Do not correct behaviour that happened more than a few second ago, or they will not know what you are correcting.
Only use their name for positive instructions, NOT negative i.e. “Well done Max” NOT “No Max!!”
Training is never finished. Training is a life long thing, with top up training essential. See them like a battery, you fill them up with training and then, slowly, they loose it and need topping up. As the old saying goes, practice makes perfect.
As the trainer, you get back what you put in.