Here are some cute behavior charts when it comes to getting along with siblings. Just write in what behavior you want to see such as: use nice words, use inside voice, control anger (ie, by going to room when upset with sibling), help brother/sister with project, read to brother/sister, etc. Do NOT write things like, "no hitting," "no yelling," etc. Those are negatives and doesn't tell your child what you want to see instead. Give them a goal of the behavior you want to see, not what you don't.
Sibs can be totally annoying, but we all have to realize that the family unit is a team. No, child #1 didn't ask to have a pesky brother or sister, but that's life! And the more they fight it, the more miserable they'll be. Sometimes one sib just wants attention from the other. So if you give both children a behavior chart with very specific, positive things they can do to improve the relationship, it guides them on how to act. And when one child gets upset with the other, remember to tell and show them what to do in each and every situation.
Click here for Free Printable Sibling Behavior Charts