What is a Good sign...

To answer last bit first.....ditch them! I guess someone is not a friend if they can't keep your confidences, only interested in their own problems not yours, does nothing to help, share or treat you despite you doing so and copies your home and personal image. Slags your partner or family and is insensitive to your feelings. Obviously this assumes that the friendship is a one way street and one party only is toxic.

If it doesn't feel right then it usually isn't. Go with you gut feeling.

If you feel a friend is toxic then the first thing you should do is talk to them about your feelings. If nothing changes then slowly distance yourself from them. Orrrrrrr you can cut them off but then that causes a lot of friction so I would just slowly make yourself unavailable.