I have a 3 year old Border Collie. She's my only pet and I would like to know how to make her happy. Please help.
You didn't give us much detail about her. What makes you think that she's unhappy? Is she mopey? Does she cry all the time? What, exactly, is she doing to convince you that she's not happy?

Give us a bit more detail, and I'm sure that someone can give you some suggestions.
will you could play whith her。