Naming is Everything
The hardest part of programming isn't algorithms — it's naming things. A well-named function is self-documenting. getUserById() tells you everything. doStuff() tells you nothing. Spend time on names.
Small Functions, Single Responsibility
Functions should do one thing and do it well. If you need to write 'and' in a function's description, split it. Small, focused functions are testable, readable, and reusable.