Firstly, when doing others' makeup I sometimes use a base that has a slight sheen (note: no shimmer). One that I like is Missha's BB Boomer which I assume was made for use with BB cream but also works well as a base for foundation. For myself I find this can be a little *too* glowy but for those who have normal or dry skin this is ideal.
For extra shimmer I sometimes use a BB cream. Lots of brands have created "shimmery" "glowy" or "watery" style BB creams that are very similar to the highlighters by Benefit. I use BRTC's Glossy Shining BB cream.
I learn a lot of Korean makeup styles from this lady on youtube: Jungsaemmeol. This is the kind of makeup artist I like watching on youtube the most - making people look like themselves with a few improvements rather than changing how people look completely. She does UH-MA-ZING makeup that looks both effortless and pristine by the end. Course it also helps that she works on extremely pretty models to start off with. I mean, if we looked like that at the start of makeup then we'd be putting makeup companies out of business on account of not needing any!
But anyhoo, I really do like watching her work her magic and in most of her vids you can see how she creates the dewy skin effect that we try so hard to replicate =)