Having a brand strategy in place before starting any design work is a must. Not only does it help position you as an expert in branding, but it guides the project in a way that keeps design refinements to a minimum (if any) and helps persuade your client on the design decisions you make, because they'll have a backbone of strategy.
01. A 27 page, editable .ai file
02. Fill-in-the-blank pages with written instruction on each page
03. A template you can use over and over again for each one of your clients