I have been on working on the issue of running out of breath ever since I started the course four years ago. I actually just had a break through with breathing on the harp over this past couple weeks. ultimately I have found that working on strengthening my lung capacity has been the greatest tool for me to overcoming this problem. There are a lot of different things you can do but one thing that has been helpful has been working on Diaphragmatic breathing to strengthen my lung capacity. The other thing that this helps with is that it gets you breathing from your diaphragm which allows you to take in a lot more air instead of taking shallow breaths from your upper body…you may already be doing this as well. I have found that when I breathe from my diaphragm when taking an in breath on the harmonica I have a lot more air to work with. The other thing that I do is just becoming aware of how much air I am spending on my in and out breaths. For instance when playing “she’ll be coming round the mountain” right before the four draws on the 6 hole there are a lot of blow notes. When I play that tune I try to stay aware that I don’t breathe out too much air if there is a phrase coming up that requires a lot of in breaths….also making sure to get a breath from the diaphragm when you start those draw notes. Its been nice lately feeling like I am starting to have more air to work with when playing to sustain the notes and not rushing them and then not ending up huffing and puffing after a song Lol! I hope that this helps and have fun!