Boston Terriers are smart and eager to please. These attributes come in handy during training. Still, they are terriers at heart; hence stubborn at times. The secret is to exercise patience and teach them one command at a time.
Also, it helps to keep the training sessions short. These sessions should not go for more than 15 minutes since they have short attention spans. Lastly, speak to your Terrier in a positive tone. Speaking to them in a loud or harsh tone can intimidate them.