Strive to maintain a good work-life balance. Burnout sucks. Your health and family are more important than work. A workplace that doesn't consider this to be the case is likely to be toxic.
As for actual software development advice... Beware blanket statements. They can help you develop a low-resolution model so you don't suffer from paralysis, but real-world problems tend to be complex and messy.
Here's an example: if you were building a traditional web app, many software engineers would probably suggest using something like PostgreSQL. That doesn't mean other database technologies don't have their place. However, PostgreSQL is able to adequately serve a large category of problems with relative ease, so it often makes for a sensible starting point. Once you become more familiarized with that domain you'll develop a higher-resolution model and you can begin to evaluate other technologies more effectively. Much of software engineering is about figuring out what tradeoffs to make.
Another example in traditional web apps is using cookies for auth. Using cookies for this purpose is well documented and pretty much supported everywhere. There's plenty of known problems with using cookies for this purpose, but the alternatives also have their own set of issues to deal with.
My final example: testing. Testing your code is great and it can be very useful, especially when refactoring or developing new features. But going for 100% code coverage is usually more trouble than it's worth. It's also very easy to end up writing a bunch of useless tests. You want to focus on the actual problem and not waste anyone's time.
It's likely burnout will really change you for the rest of your life if you don't react early enough.
It's a bit sad when you realize you'll never again be that guy you grew up and identifies as. But you also have to realize that was a person with habits that wasn't sustainable and now you have to live with that.
I definitely don't want to burnout, but I also know that I will need to work very hard for a short period of time until I can exit my current full time job and secure a full time software development position.
Do you have any advice on how to strike a balance between working very hard and knowing when you're burning out?