Quiet shell habits
A loud shell profile is hard to carry between machines. I keep a short set of habits instead of a long file of aliases I never remember.
Keep history useful
Turn on a large history file and ignore adjacent duplicates. Search with Ctrl-R before inventing the same pipeline again. If a command was worth finding twice, it was worth naming once.
Prefer small aliases
Two or three letter shortcuts for the directories I open every day. Nothing that hides flags I still need to see. When an alias starts to grow arguments, it becomes a script with a name I can read.
Read man pages in pieces
I do not finish a man page in one sitting. I jump to the flag I need, then leave. The next visit is faster because the page is already familiar.
Paste less. Type the command you mean, even when it is slower the first time.