Avoid spamming, other LinkedIn errors to form a positive impression

Spamming other users and failing to have a profile photo are mistakes that can make you look unprofessional on LinkedIn, writes Liz Ryan. Don't call yourself a guru or genius on LinkedIn, and avoid bragging about the number of connections you have. Finally, don't try to circumvent LinkedIn's rules by including contact information in your headline field, Ryan writes. Forbes (4/27)