I don't belong to any promo teams, and the teams I do participate in are the ones that are strictly business oriented. I'm not against promo teams, as many people enjoy making treasuries and playing games. It's just not for me. I don't even play the internet games that so many people love. I'm too busy taking care of my shop and family.
I honestly can't say what brings customers to my shop. The majority of my views are from Etsy SEOs, but I also get a lot from Google and other sources. In fact, a good percentage of my customers are first time buyers on Etsy. I do not do Facebook, Twitter, or Pinterest (even though I occasionally receive views from them). I also don't due ads, only re-list when an item listing has been sold or expired, or any of the other marketing ideas Etsy suggests.
Somethings I do do are read important business oriented threads to see if there are any changes I should make (and then make them) to my listings, policies, titles, tags, etc. This is because things are constantly evolving on Etsy, and you need to keep up with the important ones to continue being successful. I would love to have over 200 items listed in my shop, but try to keep the number of items at least above 100. Periodically create and list new items or new fabrics. Occasionally look at other shops to see what is selling to decide if my items need updating. Answer messages in a timely manner and try to give the best customer service I can. On last thing, I focus on what actually sells in my shop (and not necessarily is viewed or favorited) and keep producing those items in one way or another. I realize this is against a lot of the marketing suggestions that you can find on Etsy and other internet sites, but it works for me.