First, of course, you need to find the perfect stone. Look for smooth rounded stones. Maybe you have a certain design in mind. Or you can take reference of below DIY stone painting and art ideas.
Amazing Examples of Pebble Art by Sharon Nowlan.
Pebble Art by Sharon Nowlan - Createsie Creating Powerful Imagery Through the Simplicity of Pebbles Really want excellent helpful hints about arts and crafts?
Pebble Art/bride and groom