You already know you should be making projects to learn things and potentially add to your portfolio. You've read your Malcolm Gladwell, you know that you need 10,000 hours of deliberate practice. Given you're just starting out, I have a slightly contentious suggestion for you: DON'T make anything new.
Your decision-making is a scarce resource. You start every day with a full tank, and as you make decisions through the day you gradually run low. We all know how good our late-late-night decisions are. Making a new app involves a thousand micro decisions - from what the app does, to how it should look, and everything in between. Decide now: Do you want to practice making technical decisions or product decisions?
Ok so you're coding. You know what involves making zero product decisions? Cloning things. Resist the urge to make your special snowflake (for now). Oh but then who would use yet another Hacker News clone? I've got news for you: No one was gonna use your thing anyway. You