Research the breed
My pet was a gift, which my vet frowned upon. She figured since I didn't make the purchase I wasn't going to be committed to the dog's welfare. You've probably guessed from my picture that quite the opposite is true. He's like my son. That's us dressed up in Mets T-shirts for Dog Day at Shea Stadium.
As much as I love my dog, I don't think I would have chosen a terrier, though. Mainly because he's very stubborn. Our walks can sometimes be a real battle of the wills.
Before bringing a pet into your home, carefully research the characteristics of the breed so you can enjoy a pet that will mesh with your lifestyle. The American Kennel Club has a good web site for research.
I did not research the breed of dog prior to buying my daughter a puppy for Christmas. I bought a Weimaraner and she is the wrong dog for our home. They are known to have separation anxiety and we found some very unwelcome surprises after leaving her alone for any period of time.