1. Don’t add to many friends in your LinkedIn connections especially if it is random people from different industries. Others might think that you are bluffing and pretend to be a “big cheese”.
2.  Recommend related services and competitors. It makes people to believe that you are friendly person who are open for everyone.
3. Don’t answer questions if you don’t have much to say (LinkedIn Q&A service). Playing around and writing things like “Dude, you rock! I feel the same.” could hurt your reputation. It is better to have few full answers which represent your knowledge.
4. Don’t stalk connections of your friends because you can lose your business partners. You never know why your buddy added someone to connection list, what if your friend is hoping to get a job or contract from this person. Your message like “Hey, I found you on John friend list, do you want to be my friend?” can destroy everything.
5.  If you found your boss in LinkedIn don’t ask him to become your connection right away. He did not invite you first and it could be a bad sign if you make a move. Firstly, check if your co-workers in his friends list. If yes, you should ask them how they became LinkedIn connection with your boss.
6. Invite more new people, practice show that people who came after your email stay with you for a long time as friends on social site like LinkedIn. They will be the one who can give good recommendation, bring more friends, and open their connections for you.
7. Don’t use LinkedIn profile like Monster resume and don’t be free like it is MySpace. Keep neutral position and try to be friendly with everyone.
8. Show your photo in profile. It brings trust to users. Try to provide all possible information which might be interested for others.
9. Don’t be shy if you don’t like recommendation people submitted. Send this recommendation back and ask to make a correction if something wrong.
10. Communicate on LinkedIn the same way like you communicate with people in your office. It takes years to build reputation and only a day to destroy it.
11. Don’t lie. Cheap MySpace tricks don’t work on LinkedIn.

Picture source: Aside