There are the usual ways. When we go up and down stairs, we count each step. When we read a story book, we count things that we see in the pictures. There is the "twelve days of elmo christmas" book. But then... It is also good to have the toddler participate in household activities. He helps with many little things. Putting his dirty clothes in the laundry basket, putting his toys away, etc.
Now, we combine these two things, each morning:
Dad: Let's make breakfast Toddler: Can I help you? Dad: Sure. Bring over the coffee Toddler brings over the bag of coffee bean and the grinder. Dad pour beans into grinder, put cover on, plug it in. Toddler pushes down on the level: One, Two, Three,.... Twelve Dad: Thanks! Toddler: No problem! Perfect french press coffee prepared by a almost three years old.