Buy a piece of plastic canvas to use for perfect eyelet placement. Just lay it on top of your project, mark the spot with a pencil, or pierce with a paper piercer or needle. If you are trying to place several eyelets in a row (or square shape, etc.) just count over the number of little squares until you have the spacing you want, mark the spot again, count over the same number of squares again, etc. etc.

I bought a large piece of plastic canvas at a craft store for less than 50 cents. I cut a piece 12 x 12 as a template for an entire page - can use it around the page edges, across the top, or bottom, or sides, really whatever you want on your page and my eyelets are always perfectly spaced. I also use this same template to pierce my paper for hand stitching. I cut some smaller templates out of the remainder of the piece to use on smaller things like tags, frames, titles. You can also purchase (again very inexpensive) plastic canvas shapes (hearts, squares, stars, circles) and use them to mark shapes for eyelet setting or paper piecing. Also same technique can be used to mark placement of photos, embellishments , etc (I use a pencil for this). Very inexpensive, no need for allot of different eyelet templates, layout templates, paper piercing templates, etc.