Making the perfect homemade wet install solution...

I can't seem to get it right. I add maybe a drop of regular dawn dish soap to a bowl of water and it goes on perfect but after everything dries I get these spots under the shield that you can only see in direct light and they obstruct the use of the touch screen. What part am I doing wrong? I squeegee out every last bit of water before it dries so I'm thinking my solution is off...

Thanks for the help in advance!

Maybe I should add I'm doing on protectors that don't require a wet install, I just prefer doing it that way.