Twitter is an amazing tool for social networking and used properly you can find yourself with a cordial relationship even with the surliest in the twitterverse.
Used properly as *I* define it of course. These are not hard and fast rules for what not to do on Twitter
1. Block your own twitter feed. I go through my list of followers every so often, usually late at night when I'm most surly, and I block everyone who has a padlock next to their name. I won't ask permission to follow you; you don't need mine to follow me. If you block your twitter feed I see no reason you should get to come to my party in the invisibility cloak.
2. Ask me housekeeping questions about queries or submissions. Twitter is a public forum. I'm not going to tell you to take a fucking hike in public. I'm just going to remove you from my line of sight.
3. Ask me to read your book, your query or go to your website or follow you. It's an even easier decision when your ENTIRE twitter feed is asking people to read your work or follow you. Again: Twitter is a public forum. I'm not going to tell you to take a fucking hike in public. I'm just going to remove you from my line of sight.
5. Including @janet_reid in tweets that have nothing to do with me. I see all those. If you're using that strategy to include me in a conversation, it doesn't work.
If you want my attention on twitter, you're MUCH more likely to get it organically. Follow my clients, and engage them in conversation such that I see who they are talking to.
There are at least two writers I first fixed my beady eye on solely because @byseanferrell and @jeffreysomers talked to them and liked them.
Twitter is the long game. Play wisely.