- expecting people to leave comments on your blog, but not "having the time" to visit other people's blogs?
- giving harsh feedback/critiques of other people's work (because, dude, if they can't handle it, they're in the wrong business), but having a hairy canary if someone does that to you?
- giving other writers the silent treatment when something good happens to them (because you're so green with envy you resemble Kermit), and then getting pissy when people don't tweet-up or congratulate you on your good news?
- expecting writer friends to help you with your query/synopsis/opening chapter, but again, you conveniently "don't have the time" to help them (note: I realize real life happens and some people really are hard-pressed for time. I'm referring to those who are just using it as an excuse).
That being said, I don't think you should do things just for the sake of getting something in return. For example, don't be one of those people who visit three dozen blogs a day and leave comments like "Great post! Visit my blog at www.pleasepleasepleasebemyfriend.blogspot.com" Please, please, PLEASE don't be one of those people. They're almost as bad as the people who follow you on Twitter, and then as soon as you follow them back, they send you a DM that says something like, "Thanks for the follow! My new book is available on Amazon!"
People are more likely to respond to you in a positive manner if they think you're being sincere, and trust me, people know when you're being sincere. Just for the record (in case there's any confusion), pimping your book out to every new Twitter follower is not being sincere; it's tacky. The best way to get people to check out your book or visit your blog is to strike up conversations with them, be friendly, and most importantly, be genuine. If someone tweets something that makes you laugh, let them know! When a friend is feeling down because they got another rejection, pay them a kind word! Did someone's blog post make your day? Tell them! People WILL notice these random acts of kindness, and soon they'll want to check out your blog, your book, or tweet you up when you get good news.
Of course, you can take the advice or leave it; but remember, karma can be wonderful, but she can also be a bitch ;-)