How do you convince your parents to crack and get your sister and you another dog?

You must tell them all the reasons why you want one. Ask them why they won't get you one. Respond by telling them why these are not valid reasons. Try to see their side, and convince them why your side is better. If price is an issue, ask for it for a birthday, Christmas, or another holiday. They normally spend tons of money on you then anyway. If you are willing, you can save up some of your maney to help pay for it. Also, tell them that you will take care of it. Remind them that you took care of your other pet (only if you did take care of it. If not, this is not a valid technique.) If you really want to impress them, you could even write an essay on it. That always impresses them. These techniques always work with my parents.