As Leonardo de Vinci once said, "Simplicity is the ultimate sophistication." Investing and trading are no different.
I believe three things:
1) The market is psychological
2) You can profit from the market’s psychological fits and tantrums
3) Compounding is the only proven way to grow wealth over time
Trading
"Price fluctuations have only one significant meaning to the true investor. They provide an opportunity to buy wisely when prices fall sharply and to sell wisely when they advance a great deal."
- Benjamin Graham
Investing
"Compound interest is the eight wonder of the world. He who understands it, earns it; he who doesn't, pays it."
- Albert Einstein
Don't overcomplicate it.
Financial markets (and money in general) are largely psychological, so using the often irrational psychology of the market to profit from price dislocations is where the best opportunities lie.