Hello techAyan

Well, you can start making your game after the jam announced the theme

Also, i think the better practice that involved making game (as you said) is to join other game jam and enjoy your participation , There’s many jam that has started or about to start and GD game jam only had 1 month left before the jam announced.

So take your time to practice yourself and don’t forget to participate this jams 🫙. (I mean GDevelop game jam).

While it’s not starting, you can try participating in other mini-events (like Trijam, for example). I gained a lot of experience doing so.