Don't get personally attached. Be prepared to throw away something you’ve done in order to do something different. Always look for better ways of doing things.
“Good enough” is good enough for now only.
Defaults matter. The path of least resistance should always be the best path.
Maintain your standard, from the beginning.
Use task queues and batches of reasonable sizes whenever possible.
Parallize and Pipeline, whenever possible.
Complexity arises when you don't understand enough to simplify.
Code
KISS
Don't log too excessively. Collect only the data you will use.
Code becomes liability at some point.
It is easier to track data flow than state.
Desgin code with pluggable interfaces for storage, network, protocols, etc.
Work in small modules, keeping the context switching small.
Team
Teams are grown, not put together. It takes more time for integration.
Scale vertically when you can. Scale horizontally where makes sense. Applies to CPU cores as well as experts.
Don't use contractors as substitute for ordinary staff.
Other people
See yourself in other people. They are also fighting their own battles, living their boring life. Just like you.
More opinionated people are, the more you should take them with a pinch of salt.
Judge on their contributions. Imposter syndrome is a thing, as is the Dunning-Kruger effect.
Personal Development
Be proactive in learning, changing your mentality, reaching out, solving problems, improving lives, enjoying your time, etc.
Read papers. Read classics. Build multi-dimensional models based on different viewpoints and domains.
Gather news based on proximity of your location, of your interests, time, usefulness, etc.
Don’t work in isolation. Share ideas, talk new ideas and designs over with your peers.
Don't be afraid to have strong opinions, but don't forget their flaws. Listen carefully to the opinions of others too. “strong beliefs, weakly held,” -- Marc Andreessen