I decided to make my tags 9cm by 5cm rectangles, but you could create them a different shape. Remember to allow space for the hole you will punch at the end for the string or twine to thread through.
I used the internet to come up with some design ideas. If you are not too confident drawing your own designs, you may be able to find some downloadable templates online.
Ensure you have enough of a border around the edges to sew the front and back pieces of your tag together so that it won’t interfere with the tag design.