In my opinion, since you're showing your readers how to profit from servicing glass doors, you may want to add tips and reports on how to profit type of ideas, etc. how to profit from servicing "car doors", "wooden doors", "metal doors", etc.

If possible, putting an actual case study report in relation to servicing glass door business, will help.

This is because you are showing proof that your plan is workable and not simply made up and this adds confidence for prospective buyers to purchase it. It also serve as a blueprint for anyone who wants to venture in this type of business.

You may offer free support too (answering all questions about the report), as part of your bonuses.