Check if you need a model release. Photos of people can only be sold for commercial use if they've signed a 'model release' that gives you permission to use their image (children need a parent/guardian to sign). Without a release, these photos can still be sold for editorial use, as long as they were taken in a public place – eg, if you submitted a 'breaking news' shot with people in the background. If there's any doubt, always ask permission.
Write and publish an eBook. You don’t need a traditional publisher and financial backing to publish your own book anymore. In fact, Amazon.com makes it possible for you to publish your own eBook and sell it independently – with no financial investment on your part. And with Kindle eBook publishing, your book will appear on Kindle stores worldwide within 24-48 hours. Just be prepared to market it yourself on social media, your blog, or elsewhere if you expect to generate sales.