A personal list of books I wish to study this year, to get better at
"problem solving". This is ranked in order of difficulty
I wish to spend this year learning nuts and bolts type things.
Inequalities: an olympid approach --- Nice book, has an axiomatic/algebraic bent.
Mathematical circles: Russian experience
The art and craft of problem solving
Basics of Olympiad Inequalities: Samin Riasat --- quickly covers the big 12.