What are the best things I can do for early stages of COPD I have stopped smoking, I dont need an inhaler,?

I was very ill this time last year and was diagnosed with gall stones, I have these under control for most of the time, but I was being nauseas and vomiting mucas,I now find out by Dr Chris Steel that I have COPD in the early stages I only get out ofbreath every now & again. I would like to know if there is anything else besides stopping smoking (which I have done), to help me?