Write pitches. If you have located a client for whom you want to write, send pitches, which are topic ideas for articles. Write pitches that not only show your expertise, but also demonstrate your enthusiasm for the topic. First, read the publication to which you are sending pitches to familiarize yourself with what they publish. If applicable, identify a specific section and send our pitch to the appropriate editor. Also, include a brief summary of who you are.
If you have a good idea for an app, and the skills to create it, then producing your own premium app can be profitable. However, with so many free apps available, it may be hard to convince people to pay. If you want to go down the premium app route, consider having a basic free version to encourage people to download the app in the first place. You can then provide the option of upgrading to a premium plan once users realize how useful the app is.