Measure your space
Understanding the dimensions of your space will help you choose your stencil size.
Make sure your tape measure is flat and straight.
The great thing about stenciling concrete is you're not limited on size or design.
You can use any stencil! (That has repeat marks of course)
Go big and bold, or intricate and interesting, it really is all down to personal preference.
I've popped some different examples below: