https://ui8.net/smotrow-design/products/the-professional-style-guide-kit--indesign-format

This Identity Style Guide was created by Smotrow Design to provide the guidelines that explain how a brand should be used internally and externally. The document provides detailed instructions on how tangible elements of a brand should be used in all forms of branded communications — from business cards to ads, from packaging to signage, and everything in between.
1. Increase the perceived value of your services. It is not enough to just do your work well. The essential part of the whole design process is how professionally you sell your work. It reflects on your earnings, reputation, and future projects. This Style Guide template will help you to be confident in the work you deliver and present your design on the highest level.