Sandpaper ... you can buy dots of it in the hardware store. Saves cutting and glue already there.
Perhaps some 2-sided tape on your template?
I don't use paper templates, though when I have had templates in acrylic, a small rotary cutter zips around the edges pretty quick.
If they are templates you'll use a lot, for a very low cost, a glass cutting shop could cut them easy enough for you. Mine puts a hole in them, so I can easily string all together that are a set.
I've also heard of folks using old tupperware lids, or yogurt lids, etc. to cut out templates, so they have something more substantial than a piece of paper .... that I'd soon cut it up with the rotary cutter!