The best advice I can give for keeping business in the LQS is to hold great classes with wonderful instructors. I am extremely lucky to have a phenomenal LQS very close by, and I go there several times a week. I take as many classes as possible, and will continue to do so. Classes increase customers' skill levels and help them become more interested in new techniques - which requires purchasing new supplies! Fantastic classes are a must. Too often I see LQS's that have (in my opinion) poorly thought out or designed classes, especially beginner's classes.
That being said, having a friendly attitude also increases business. I, too have experienced poor attitudes as LQS's, though not at the one closest to me (they are always fantastic). I, too, vote with my wallet, and spend my money at the shops that I enjoy, rather than those that make me feel uncomfortable. It was interesting to read people's comments about rudeness at LQS's. I was never sure why I was sometimes treated poorly, but I always thought it might be my age. I started frequenting LQS's and LNS's when I was in my early 20's, and was always the youngest by several decades, and I had to face a lot of comments about me "being in the wrong place," or "not really knowing what the store was for," or my favorite, "are you shopping for your Granny, dear?" It's hard to feel welcome with those comments. I guess it's not just age, though, some stores must just have rude staff or owners.