Often described as a "chameleon," Peter Lynch adapted to whatever investment style worked at the time. It is said that his work schedule, the equivalent of what we would call today "24/7," did not have a beginning and an end. He talked to company executives, investment managers, industry experts and analysts around the clock.

Apart from this punishing work ethic, Lynch did consistently apply a set of eight fundamental principles to his stock selection process. According to an article by Kaushal Majmudar, a CFA at The Ridgewood Group, Lynch shares his checklist with the audience at an investment conference in New York in 2005:
Know what you own.

It's futile to predict the economy and interest rates.

You have plenty of time to identify and recognize exceptional
companies.

Avoid long shots.

Good management is very important - buy good businesses.
Be flexible and humble, and learn from mistakes.

Before you make a purchase, you should be able to explain why you're buying.

There's always something to worry about.

In picking stocks (good companies), Peter Lynch stuck to what he knew and/or could easily understand. That was a core position for him. He also dedicated himself to a level of due diligence and stock research that left few stones unturned. He shut out market noise and concentrated on a company's fundamentals, using a bottom-up approach. He only invested for the long run and paid little attention to short-term market fluctuations.