How to get better at Combinatorics for Math competitions and the International Math Olympiad?

Book Recs: Arthur Engel - Problem Solving Strategies Pranav Sriram Olympiad Combinatorics: https://cdn.bc-pf.org/resources/math/... Topics: Extremal Principle Algorithms Invariance Games Counting in Two Different Ways Graph Theory Coloring Proofs The Box/Pigeonhole Principle Induction Competitions: Tournament of Towns: -- https://artofproblemsolving.com/commu... -- https://www.math.toronto.edu/oz/turgo... EGMO: -- https://artofproblemsolving.com/commu... JBMO: -- https://artofproblemsolving.com/commu... Romania: -- https://artofproblemsolving.com/commu... ELMO: -- https://artofproblemsolving.com/commu... Russia: -- https://artofproblemsolving.com/commu...