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.
If you’re a musician, writer, artist, tech nerd, pundit, or can produce any type of audio, video, or text worth consuming, you may be able to sell some stuff in Apple’s flagship iTunes store. By selling your work here, you’re able to stand next to the marketing clout of big business. You can make a healthy living off the iTunes store, and there’s no better time than now. Learn more about iTunes with this lifehack.
If you’re a skilled worker in a specific niche, like marketing, design, or software development, there are specialty marketplaces that cater just to you. These are amazing places to make money online as you know that the people visiting them are looking specifically for the skills you have. Check out places like 99Designs or Dribbble for designers, Cloudpeeps for marketing and SEO professionals, and TopTal, Crew, or Gigster for high-level software developers. Once you've built up your development skills, you can begin building a brand for yourself as a higher-value consultant and start charging brands for larger projects like implementing an entire WordPress security overhaul or migrating a website from http to https.