It depends on your skills, may be one of the following:
- Programming (which languages).
- Database administrator.
- Domain administrator.
Based on that, you choose your project.
If you are in the field of networks and you can do it for companies and buildings completely, then it perfect and the demands are high in the markets, especially if you can contract with construction or development companies. However, if you are a programmer, it depends on your specialties, whether programming a phone, a website, or all of that, plus your speed and standard, and by that, you can determine the targeted group.