Children like rhymes with repetitions. So I'd like to share a rhyme with you, which will help to learn counting from 1 to 12.

I have a big clock
All day long it goes Tic-Toc
But every day at 1 o'clock
It goes BONG.

I have a big clock
All day long it goes Tic-Toc
But every day at 2 o'clock
It goes BONG, BONG.

1. Repeat this rhymes with as many numbers as your child knows. For example, repeat the rhyme only three times if the child can count from 1 to 3. When he (she) can count from 1 to 12, then you will learn the whole rhyme.
2. Make your own clock to learn the rhyme. It will be more fun!
3. You can use actions with this rhyme too.

I have a big clock - draw a large circle in the air.
It goes Tic-Toc - move yor index finger from side to side.
At 1 o'clock - hold up one finger.
It goes BONG - say it loudly and clap your hands.

4. Let your child say BONG, but you count the number of BONGs as it is easy for a child to lose count with a number larger than 3.
5. Don't always work consecutively. You can go from 1 o'clock to 5 o'clock and then back to 3 o'clock. In this case children need to listen carefully to give you the right number of BONGs.
6. When your child knows the numbers and the rhyme really well, you can stop saying the numbers and just show the clock face. The child will read the number from the clock and give the right number of BONGs.

The idea is taken from "Early Numeracy".