Not much to say about the subject that hasn't been said already.
I try to avoid them at all cost. I use action or thought to help the reader understand who is talking.
"Can you come to the mall?"
Normally Heather would jump at the opportuinity to go to the mall with Sally. But she did't want to run into Kevin and his new girlfriend who were going to be there. She might have told Sally that she had no more feelings for the football player, but she was fast learning that it took longer than a week for a sixteen year old to forget her first love. For the next three months, she needed to avoid any friends during the summer vacation. Maybe by September Kevin would be a thing of the past.
"Thanks, Sally, but I have plans."