I grew up as a musician, playing bass in orchestras and bands. Being in a band for a show means that you join at quite a late stage in the rehearsal process: everyone has already bonded. Through working with the American Repertory Theatre, I found I had an aptitude for working on audio and my career has developed from there.
I think to be an effective sound designer, you need to be a good listener (as opposed to just having good hearing). You have to listen well.
If you’re an aspiring sound designer, there are a lot of different free computer programmes you can experiment on. Of course, technical training is great and very beneficial but at some point you just have to DO IT. You learn through mistakes and successes so you need to go for it!