How do you decide which project you want to work on next?

The one that's most high leverage!

If you have a solid long-term work plan, all your projects will be run one by one without backlog problems and delays. Task prioritization is also an essential point you should pay attention to. Make sure you've chosen a proper project management tool that will help you decide which project you want to work on next. Good examples are Wrike, Orangescrum or GanttPRO.