For a long time I used a 30PG/70VG mix, after awhile that seemed to get harsh, and hot.
Recently I have been using a 20%PG/70%VG/10%distilled water, and the vape is not harsh or hot anymore, distilled water will make the juice thinner it has a consistency of a 50/50 mix. Also adding water to the mix lowers the temp needed to vaporize the juice, and makes the vape cooler, kind of like when you add water to antifreeze, it lowers the boiling point. Adding water will also reduce the watts needed to vaporize the juice.
I'm not saying everyone should add water to their juice, just saying what worked for me, some people like a harsh vape with a lot of throat hit, but not me.