1. Twitter rocks - as a way to interact with people. I have made new friends from all walks of life (though my feed seems disconcertingly DC-heavy!) We talk politics, pop culture, sports, the weather, beer... It is social media, after all - don't be a-social!
2. Emanating from #1, and suggested by @KHayhoe: Do not use Twitter solely as a press release, and do not send auto-DMs - "Thank you for following me! Look forward to interacting with you!" - if you don't really plan to do so. This often happens with folks who follow (and are followed by) tens of thousands of tweeps (see #6). If I don't see you interacting with your followers, it's highly unlikely I will follow you.
3. Obviously, there are exceptions. These are primarily:
(a) politicians (@BarackObama!);
(b) real celebrities - authors and movie stars with a substantial body of work behind them (@iamsrk) come to mind; and
(c) reporters - see #4.
4. My other major use of Twitter is as a news-feed, from journalists in fields I am interested in: politics (@markknoller, @jaketapper, @chrisgeidner, @anamariecox, @ktumulty), sports (@SI_PeterKing), the environment (@drgrist, @kate_sheppard), and local news (@mistymontano). Their feeds are often filled with insights on, and links to, news outside their own work, and you might notice that these fine folks interact with ordinary people like me :-) That is NOT required, as they are busy chasing down interesting news stories for the rest of us.
But given the choice - and there are choices a-plenty on Twitter - I follow the folks listed above, instead of @DavidGregory.
(Perhaps one "real-world" advantage: I watched ABC's This Week while Jake Tapper hosted it and teased it via Twitter, in addition to interacting with his followers about the show. But I skip David Gregory's Meet the Press.)
5. Follow-back/Unfollow: See #1. If I follow you, that means I find your feed interesting. But (despite my delusions of self-importance, see #4!) I do not expect a follow-back. This works in the reverse way too - please do not expect a follow-back.
But I will usually follow you back, at least for a while, if your Twitter profile has a decent bio/web link (so I know who you are - the human connection) - this is important.
If your feed overwhelms my feed, or does not hold my interest, or has very little to no original content (e.g. if all you do is ReTweet others without even adding commentary), I will unfollow. (Unfollow me if you will.) I also unfollow inactive accounts from time to time, but obviously that does not affect you.
6. If you are a "Social media" or "marketing" expert with tens of thousands of followers/follows, do NOT expect a follow-back (and in any case, you are unlikely to be reading this post). I just do not believe meaningful human interaction (see #1) is possible at such volumes.
7. Porn/sales bots WILL get blocked. Since politics is a big part of my feed, I will unfollow or even block (a) single-issue ranters (since I already know your point of view on your pet issue, following you is not going to inform me further); and (b) folks on all sides, if you have no respect for human rights and civil discourse.
8. Finally: This is me. (Since this post will replace my bio link, figure I should link to my personal website here.) UPDATE: In the interest of full disclosure, my political leanings (thanks to OKCupid!), and reasons why I still don't call myself "liberal" or "progressive", despite what OKCupid says!