I hope this helps!
Here is a step-by-step tutorial that should help you create even and centered lettering.
First, count the characters (including spaces) that you will need. In this case, POLICE BOX (9 letters + 1 space = 10 characters).
Second, find the middle letter(s). In this case letters 5 and 6 will be on either side of dead center. You can eyeball dead center or use a ruler to find it.
Start the painting by writing "CE" in the center. Then add the letters to the right, making sure to keep the spacing and size even.
Now, working backwards from the "C" add the "I", "L", "O" and "P."
Let it dry and then flip and do the other side.
|I use this type of fabric paint.|