A few people to follow and/or hashtags that I find useful are:
Jimmy Casas - casas_jimmy
#iaedchat - Iowa Education Chat
#edchat - Education Chat from people across the world
David Geurin - DavidGeurin
Todd Whitaker - ToddWhitaker
I also will add that I really like TweetDeck. You can customize this site/app to follow specific hashtags and people.