The sign for excuse me is also the sign for pardon me or forgive me. You set up the sign by taking your non-dominant hand palm facing the sky, then brush along your palm with the fingertips of the dominant hand.
We remember this sign by thinking of a small child, brushing your leg with their hand to get your attention and saying excuse me.
Manners signs like please, thank you, and excuse me are good signs for older children that have a larger vocabulary and have a more developed understanding of the world. These signs are a good introduction to the ideas of gratitude and courtesy. Teach your child to sign excuse me to get your attention instead of interrupting, yelling, or throwing a tantrum. When they try and get your attention in an impolite way, do not give them attention. Instead, remind them, "Say excuse me when you want Mommy's attention," or, "Remember to say excuse me." And be sure, when they do it the right way, to reward them with your attention, or if that is not possible, at least some acknowledgement.
Use the excuse me flash card when introducing your baby to basic manners and appropriate responses in social engagements. For example, have them sign excuse me prior to interrupting a conversation or when sneezing.