First off, write down every idea you have. Even if they’re bad, they’ll come in handy later in one way or another. Maybe they’re good enough as-is for a different game, or maybe they’ll amalgamate into something more with other “bad” ideas. The point is, you’ll save yourself a lot of time and make better games if you have a large stock of ideas to recruit from — just remember to not overload your current project with too many outlandish ideas that’ll lead to scope creep. In addition, find ways to prototype quickly. Some ideas are better than others, but you usually don’t know for sure until they’ve been playtested. Get something like Game Maker Studio or Unity that you can use to create super quick prototypes (as well as full games) and you’ll save yourself a lot of frustration later. You can also branch out and use an engine that you’re not accustomed to for things like weekend game jams that’ll help break the monotony of working on one project for ages.
Even if you’ve tested those prototypes yourself, let other people test them out too! There is something that I like to call “parent syndrome,” and it isn’t exclusive to game development. Basically, you are much less likely to notice the flaws in something you have dedicated lots of time to, such as a child or a game you developed. You’ll likely miss fundamental problems with your game if you’re the only person who takes a look at it, so get someone else to criticize your prototypes for you. Do this early, as you don’t want to discover gigantic problems late in development. I know I’ve had a ton of small games that I thought were pretty good until I showed it to a playtester or a game design colleague and they rattled a billion things that I needed to fix — if you’re working on a project, sometimes you’re way too close to it. Get external advice.
Once you’ve found something you truly feel has potential, don’t think too deeply into it! Keep things simple, as when you’re working solo it’s very easy to overwork yourself with feature creep. Go for a simple and stylish aesthetic (such as Undertale) and focus on making the game fun to play. Additionally, if you’re new, don’t try to make a masterpiece out of your first game or two! Your lack of experience will become much more obvious if you’re pursuing something you need to work incredibly hard on, so build up experience with some decent games first and focus on that masterpiece later on. Heck, even if you’re a seasoned developer working on your 24th game, focus on the day-to-day before focusing too hard on the final vision. Remember that a shipped game is worth much more than a game that’ll never get done. Focus on getting the work done every day, and the rest will take care of itself.
When you go to work on this game, try to make a plan and stick to it. Even if your estimates are wildly wrong, and they will be, you should have a general idea of how long you want development to take. Now, take that number and multiply it by at least two — this is the more realistic time for development. If this is your first game… multiply it by a factor of five. You’ll find that your game deviates from your original thoughts as you continue development, and this is fine, but be careful if that deviation causes the game to become bigger than it originally was planned to be. Feature creep can be good for a game, but often times it’ll cause the game to never be finished. Set a strict limit on how long you’ll let yourself work on a project, and plan for any port requirements in advance. It’s much more important to get a game out onto the market in a decent state than to focus way too long on a game that’ll never hit the market because it isn’t going to get finished.
My final tip for you is to not overdo it. You don’t have to be a perfectionist when you make your game, and you aren’t expected to be one. Aiming to fix every little problem in your game is a death sentence for your productivity. Obviously, you want to make sure it works well, but accept that your first few games might be below some of your standards for perfection. Also, when you get feedback on the game, don’t overreact to it. People can often tell when something is wrong, but they don’t always get the reason right. Go with your instincts and fix whatever you think is wrong personally, no matter what your testers say.
Important Takeaways: Write down every idea you have, as even the ones that you may think are “bad” may become useful at one point or another. Take your ideas and prototype them to test their quality quickly, and get others to also test them to make sure there aren’t any problems that a developer bias hides. Plan your schedule, but don’t worry too much if you can’t meet a specific self-imposed deadline. You only have to be worried if feature creep is pushing your finish date way past the deadline. Finally, don’t overdo it; don’t be a perfectionist and accept that your first few games might not meet some of your standards.