Using social media has a lot to do with sharing and giving. The idea is that us web users would give our contribution to this vast pile of everything.
Therefore if you want to be a social media good guy, you will give. For free. Give information, give your knowledge, give advice (to those who ask for it), give ideas.
Do you have a blog about design? Think about giveaways, gifts you will send to some lucky ones who have joined the competition by commenting your blog or retweeting a certain tweet or what ever it was.
Don't just take. Give something and you are more likely to get something: Get readers and comments for your blog, get Twitter followers and Facebook likes, get customers, get sales, get others do marketing for you.