Trying to build up your GitHub repo for the sake of job applications is the wrong way to go about things.
In general, the first thing that you should be doing is building up your knowledgebase and skills. Are you looking to go front-end, back-end, or full-stack? Focus on one of those and learn, study, & practice. You should code as often as you can, but not all the code you write should necessarily go on your GitHub repo (leave really basic exercises and “Hello World” templates on your local computer).
Keep in mind that before most recruiters or hiring managers even bother to check out your GitHub profile, they’re way more likely to review your resume and LinkedIn profile first. If either of those don’t pass muster, they’re not going to bother looking at your GitHub. So work on those first, before trying to build up your GitHub repo.
Also, something else you should keep in mind that having an active GitHub repo doesn’t mean you’ll get extra consideration for any jobs. If you’re trying to build it up for more job consideration, that’s a totally backwards approach. There are lots of developers in the world who are extremely active on GitHub—you’ll never beat them for starters, and chances are pretty good that someone with more active GitHub history will apply for the same job as you, so that really won’t help you. Focus instead on building just one really cool project if you’re going to take the GitHub approach.
Also, remember that putting up your own projects on GitHub is just one way to show activity. You can also collaborate on a project with someone else you know, or contribute to an open source project. That will help you learn Git better too, as you’ll have to use branches and pull requests.
Seeing as you haven’t posted any code on FCC, or a link to a portfolio site, I have no way of guessing what you currently know. But if you’re looking to get job-ready, you absolutely need to have solid knowledge of HTML, CSS (and one of the preprocessors like Sass, along with one of the methodologies like BEM or SMACSS), and client-side JavaScript (both ES5 and ES6) at a minimum. One of the front-end frameworks would be highly recommended too (Angular, React, or Vue). If you don’t have this solid grounding yet, that’s what you should be focusing your time on first. All of that will give you the knowledge to build something really cool.