How bout just plain ole studying hard?
I bought a recent elementary math book from a thrift store a few years ago. Talk about BS. I’ve had math past calculus and I found the book obtuse. Math is, in a sense, modular. With practical examples and a mastery of basic math including multiplication and division, a student has a solid foundation to build on. The new math fails to do that.
Studying hard is just one tool in the box. You still need effective teaching.