To sign almost, hold both hands up in front of your body, palms facing up and fingers held together on each hand. Then, while keeping the non-dominant hand steady, flick your dominant hand upward while touching the fingers of the steady, non-dominant hand once.
Flick the fingers of your non-dominant hand gently, barely touching them in fact, as if to indicate that you barely missed something, or you "almost" did it, but not quite.
Teach your child the almost sign in the context of games, sports, or activities that are nearly completed but don't quite hit the mark. Use this in conjunction with motivating your child to keep on trying, so that they are encouraged in the process.
This is a useful flash card taught best in conjunction with real-life experiences. When your child shows effort in doing something (building blocks, getting dressed on their own, tying their shoelaces, or zipping up their jacket), but doesn't quite fulfill the action, tell them they've "almost" got it, but that is okay. They just need to follow your example and try again.