Don't try to write complicated code on purpose to show how smart you are.
"Clean Code" by Uncle Bob
###You ain't gonna need it (YAGNI) applies most of the time. In general, just design for today's requirements, to prevent over engineering
That includes your manager. It's your job to elicit their true needs.
There's usually more than one way of doing things. The term "best practice" is overused. There are some good practices in software development, but beware someone telling you that something is the "best" way of doing something.
###If you don't design for scalability, your code won't scale.
Same applies for all.
Try writing tests before code
Don't ask permission to refactor, test, document etc. It's all part of "programming". Don't ask permission to do your job.
###Care about your work. Care about your customers. The code we write allows the users of our code to get their shit done, without our software getting in their way.
"what problem am I trying to solve"?
In general, stick to solving one problem at a time. When you spot other problems, note them and come back to them later.
This is a life lesson that applies to software development. When you commit to doing something, focus on doing it. When your washing the dishes focus on washing the dishes - forget all the things that stressed you out that day. If you are spending time with your family, be there - turn off your phone, forget that tough problem you've been wrestling with. When you're in a meeting, participate - focus on the conversation and forget about the work that's piled up.
SRP has broader applications than just to code.
Start with a brute force algorithm until you find a reason to change.
You will never know everything - that is impossible. Keep learning, but don't get caught up on what you don't know
Computers get away with it because they can context switch really fast (most of the time). Context switching for us mere mortals has a high cost. Do one thing at a time, and do it well.