I think one of the mistakes I made the most when starting to get into game dev was the trap of overscoping. I feel like it's a common beginner mistake - dreaming up this insane concept for beyond your skill. You'll work on it like crazy and be super passionate about getting it done. But not a week into the project you realise that it's a lot bigger than you realised. This ends up absolutely wrecking your motivation and makes you wanna quit completely. Even today, sometimes I start a project that I feel like I can finish but I just can't. The most recent example being 'Zelda Snowland'. I would LOVE to gush about that here but I'll eventually give that it's own article. Point is, you need to know your limitations. There was this time I was making this game called 'The Red Door'. I think it was for a game jam? I had a whole opening cutscene, an NPC with dialogue, which I was super proud of at the time because I'd been wanting to make a dialogue system for a long time before that. But when I got passed creating the opening section of the game, I didn't really know where to go next. It was because despite already pouring in hours to make the game, I didn't actually know what it was going to be. And sometimes that's fine but it can be really frustrating, which is why nowadays I would only start development if I already have a clear concept in mind. I'm still glad I made Red Door though. The thing that makes game dev fun is that each time you make a new game you'll probably learn something new. So for Red Door I learned the basics of a dialogue system, even though it was pretty rough. For some of my older games I learned how to handle collisions and object interactions. And so on and so forth until eventually you know enough to make a competent and playable game
If you're just starting off then I think probably one of the best ways to learn how to make games is to just make small games that already exist. That way you don't need to spend days and weeks coming up with a concept. You can just look at the final product and go, how did they do that?
GMTK has a great series about developing games that I reccommend checking out for how to get started. His whole channel is dedicated to game development so it's a great place to explore that kinda stuff.
Game Development is just like any other skill - it takes a lot of time and patience to get really good at it. And also just like like any other skill, you should really only do it if you enjoy it. If you're reading this and you haven't tried game dev, I highly recommend it! Even if you can't code or draw or make music - we all gotta start somewhere!