I've sent a pretty generic follow up asking for reviews and left a link to channels i was looking to promote. I found it on a small business forum, I had good success with it. People were very responsive, it washed a negative review I had on yelp that was near the top that I had a couple customers comment to me about. I haven't been consistent with it though.
"try to become not a man of success, but try rather to become a man of value."