Your concern is valid and it is one that many struggle with. Fortunately, many others have also found a way to get it done, meaning that you can too.
Passion is an important aspect. Without the passion for both your job and your startup, you will not be able to juggle both. If you can find a startup idea that is more like a hobby that you do in your down time, it won’t be hard for you to make time to work on it. To go one step further, don’t feel like you have to turn a hobby into a business. The converse is also possible, you can turn a business into a hobby if you run it properly. The key is finding balance and “blending business with pleasure,” if you will.
Patience is another tool that will help you, especially if you are just starting a new job. Despite your concern for being “stuck in the rat race” understand that your job is what will provide the capital for your startup so don’t be in too much of a rush to start building your startup. You want to make sure you are ready first.
Building a team will be important to your success. At a certain point, you will no longer be able to do every single thing, so you will need to recruit a team that you can trust. Hopefully you can find team members that bring the same passion as you. But if not, it’s okay, just know that you may have to provide them with extra incentives so their motivation matches yours.
Finally, overall drive and work ethic may be the most important factor to getting you through. You know the work will be there so it is up to you to rise up and get it done. It is up to you to find a way to make the time to work on your project. It can be very rewarding to build something of your own, but it is also very challenging. The reward is definitely worth the challenge if you ask me and I wish you luck on your endeavor!