Honestly, find an existing project in your language of choice with an active maintainer and start fixing tickets.
You start a new project, odds are you're stuck maintaining it for years, and it becomes a job, or it dies. IME, it's far better to find a project you yourself use and like, that you're capable of contributing to, and doing that. Start popping stuff off the bug list, if you're a hero, or implement that missing feature in the backlog that you want. Your commitment to the project is a patch. Or, maybe you like working with the project and you become a long term contributor.
That's just my recommendation. I'm not saying don't start something new; just, if you're looking around for things to do, and aren't passionately trying to scratch an itch you haven't found a solution for, you're most likely just going to create a throw-away project.
Just my opinion.