The first time you ever try salvia, little is likely to happen. It takes a single use for the receptors to start building in the brain stem region. Wait a few days to try it again and you'll get the full effect.
Also note that salvia has reverse tolerance, meaning that the more you do it, the stronger it gets. If you start at 15x you will eventually have to go down to 10x, etc. But that would require frequent use and most people don't do it that often.
Another piece of advice is that you can mix it with cannabis. You can either smoke the cannabis first and then do salvia, or mix them together. After the initial salvia peak, you will have weaker closed-eye visuals for up to 90 minutes that have a salvia signature. Lots of green and blue swirls. They're best viewed in a dark room.
I used to do salvia every night because for a time it was the only substance that cured my insomnia. One toke and after the peak high I was out like a light. I've since moved on to more practical sleep aids.