Boxing
Looks like you’re “putting up your dukes.” Like the sign for boxing, many sports signs are iconic.
Drive
Pretend that you’re steering a car.
Eat
Act like you’re putting food in your mouth.
Milk
Have you ever seen a cow being milked? That’s how you sign milk.
Swimming/pool
Think of when you walk through the shallow end of the pool and extend your arms out in front of you to clear the water.
Toothbrush/brush teeth
If you’ve ever brushed your teeth with your finger, you made the sign for toothbrush and for brushing your teeth.