You can only make money by helping others. Every startup that's successful is based around providing value and being of service.
Money was invented to exchange it either for goods or services. Paying someone and not getting anything in return is a rare case.
So, don't focus on making money. Focus on being of service and how can you help people, when they actually need it. That's when they would have an inner urge to pay for the solution you provided to their pain point.
If you have experience in sales, that's Awesome! You can use your experience to help people who are looking for a person to generate business leads for them. You can get paid easily by people who need your assistance, and are assisted by you.
You make money by helping others by addressing a "need."
Research current trends, attend tradeshows, try writing a book, try to engage in public speaking and maybe dabble into education.
Door to door sales is a lost art and doesn't work anymore in my opinion. E-commerce and window shopping are taking over the trends and people are so well educated with what today's trends are that most people won't even welcome a door to door salesman anymore in the same way. Maybe look into creating your own marketing company and use your sales and canvassing experience to teach marketing techniques.
Create classrooms, lesson plans and packages and teach your marketing skills to people. When it comes to marketing, the cool thing about it is that there is no such thing as a wrong answer. Marketing is all subjective and it's up to the end consumer to believe you and follow your advice or not. No harm, no foul.
Likely what you're really asking is how to do effective lead generation.
Where "effective" means locating new clients at near zero cost who can pay you $1000s every month, week, day or hour.
Get in front of groups of people with money.
Simple way to do this. Join https://Meetup.com + attend many business + networking events.
Watch + Learn how speakers, group organizers, attendees all "work the room".
Attend a few of these groups + you'll be generating more leads each week than you can process in months or years.
Helping others in nonprofit settings is always an option, though making money at high and sustainable levels is not always a certainty, especially when you're first starting out. It depends on the nonprofit model you're working with and the type of service provided.