So, your children are ready to begin counting?! First, you want to start with one-to-one correspondence ... touching each object as you count and associating the oral number with a bunch of objects. As you are counting blocks, touch and say, "one, two, three - I have three blocks!" You should see your child copy this behavior, after some modeling. Then, play games to see who has how many - I have three cars, how many do you have?
After children understand that groups of objects can be assigned a word (numbers), show them what numbers look like! Show numbers in text and play a find the number game. There are many counting books available, with fantastic illustrations, to help generate interest! Whatever your child is interested in, there is probably a book that shows counting and numbers related to it! Eric Carle's wordless book, "1, 2, 3, To the Zoo!" is a favorite to start with. Look for Dinosaur counting books, books with fairies, etc., ... there is something for everyone! "Over in the Meadow" and the "Five Little Monkeys" books are favorites for rhyming songs with numbers.
When your child is ready, look for numbers in other printed material, such as newspaper flyers and mailers, and make separate collages of each number - work on one number at a time. Use Legos to "build" the number and talk about how it is formed. Play some silly finger plays like "Five Little Monkeys Swinging in a Tree" to reinforce the number names, too!
When you're ready for hands-on number making practice, use the different letter forming fun tricks mentioned in former posts! You can also find heavy-duty plastic paper protector sheets for 8 1/2 by 11 paper and make some templates to slip in. Then, practice with dry erase markers to your heart's content :) Some children like to practice using a Rainbow Write technique, which is to form the number with a pencil very nicely, and then go over it for repetition with many colored pencils.
Take it step-by-step and only introduce the next step when your child is ready. Frustration is the last thing you want your child feeling! Have fun!