If you are practicing insight then noting thoughts is very important. Consciousness (the knowing part) knows thoughts so thoughts cannot be a permanent self. If you have analyzing thoughts you can note them and watch them naturally pass away. Trying to stop them is like trying to stop anything else and it includes a little stress. If you think "I don't want to think about that" the brain locates what you're trying to not think about and poof! you're thinking about it. Just recognize it's there and don't add anything or try to stop anything. It goes away on it's own if you let it. Noting with verbal talk is only okay at the beginning but you want to note what is already hitting consciousness so no verbalizing is needed. Try staring at an object until you recognize what it is without the verbal part and you can get what I mean about noting without mental verbal talk.
Shinzen Young has a good explanation of what I'm talking about. You want to pay attention to what's in your experience more and more and including more and more of the background of what you think is a you (thoughts/images/intentions/movements/actions). To do that properly means there's little time for analysis because there's too much to notice.
Return to the sourceIf you want to do concentration first then you have to stop thoughts except for thoughts of the breath. You would acknowledge thoughts arising and as quickly as you can (without further analysis) bring the mind back to the breath over and over again. The trick to understand is you don't need a huge thought process to find out how to return to the breath. Just do it.

Maps are there to guide you when you actually have an experience you can't explain, not before.
Some other good resources:
How to note and labelGil Fronsdal - Mental Noting