One thing I’ve learned by simply reading other tweets. You don’t want to come across to people as an annoying non-stop commercial that never ends. Make sure you actually tweet good, funny, wise, or interesting tweets. Only plug your product, event, etc., when it’s absolutely necessary and do not overly re-post.
Tried and true. Always follow back new “followers” and give them a shout out by tweeting something like “Thanks to all my new followers @SoCalSurferBats, @RyanShepard”. It shows you are grateful, which is well recepted.