The general rule of thumb for layering serums is lightest to heaviest.

Here is an example of a regimen with acne and healthy aging products step by step

AM

Cleanser

Toner

Hydraboost/Hydrating Rain
Vitamin C Complex
Mandelic Acid Serum %
Advanced Multi-Peptide Serum
VI Derm Dark Spot Lifting Serum
Moisturizer
SPF

PM

Pre-Cleanser

Cleanser

Toner

Hydraboost/Hydrating Rain
Vitamin A with EGF (on the nights you DON'T wear Acne Gel)

VI Derm Dark Spot Lifting Serum (you can apply this on the nights you wear Acne Gel, and only wait to dry, you DON'T need to wait 15 minutes.  

Moisturizer (on the nights you DON'T wear Acne Gel)