"No" Is Not Enough Information
Of all the commands we give our dogs, "no" is probably the most frequent and least productive. In human terms, imagine going to work in an office where your supervisor introduces you to your job in this manner: "Here's the office. I'm not going to tell you what your job is, but, every time you do something that's not part of your job description, I'll yell out, "NO!". How long would you be willing to work under those conditions?
"No" is simply not enough information, because it keeps the dog guessing about what is a legal behavior.
I like to call no a "place holder". A "place holder" cue should be something we can use to interrupt a behavior...until we gather our wits and give the dog a cue that replaces the behavior with something better or at least something incompatible. Before your head starts spinning, let me give you an example:
You dog may jump for joy when you get home. An incompatible behavior cue would be "sit" because if he's sitting he can't be jumping. Now you can calmly and quietly scratch your dog under the chin (if they are capable of sitting still) or you can grab a toy and toss it away from your body and say, "go get it". Again, he can't be jumping on you if he's chasing a ball. If you do this everyday for a month, the dog might start sitting instead of jumping or arriving expectantly with his ball, backing up slowly as he positions himself for a flying catch! But, you have to establish the habit.
Let's say your dog is barking at a squirrel in the yard. If you go out and say "no bark" (I still can't understand how that term became so popular), the dog doesn't understand that you mean for the next hour...or forever. So, they stop momentarily and you think you've got it all under control. Then the dog starts to bark again. He's done everything you've asked him to do, but now you're mad. The incompatible behavior cue I use for barking is "come" (which you need to work on daily with any dog). When the dog gets to me I reward them and then...and here's the big reveal, I take them inside the house and offer them something more productive to do, like a bully stick or a dog puzzle.
You have to remember that "no" isn't enough information. The dog has to do something, so ask yourself, what is a reasonable behavior for each undesirable situation . You can't say "no" and expect the dog to know what it is you actually want him to do.