You're contacting people from LinkedIn on your phone

LinkedIn's mobile app lets you connect to people with a click—but you can't customize the message.

People will say to me, "Well, I didn't personalize my message because I couldn't on my phone," says Brown. "It's not an excuse. Get on your computer and connect that way."

You also run a greater risk of typos on your phone. It's always best to conduct the bulk of your LinkedIn activity from your computer, where you have all the features available.