The more you know, the less you carry.
Mors Kochanski, wilderness survival expert.
Writing and sketching.
Card-sorting.
Diagrams.
Interviews.
Spreadsheets.
Workshops (structured ideation and synthesis).
That’s my toolkit, more or less, for most design problems.
The further I get into my career the more affinity I have for simple and sturdy intellectual tools that can be applied to any number of situations. Give a skilled survivalist a knife, good shoes, and a bit of rope, and they’ll be just fine.