The speaker, Warren Buffett, states that if he had to start over with under $1 million, he would focus on in-depth research of small companies, similar to how he previously studied railroad companies in the Moody Transportation manual. He believes this approach, combined with a genuine passion for the subject matter, is essential for achieving high returns.

• The speaker would focus on deep research and analysis of smaller companies, similar to how they used Moody's Transportation manual to find interesting opportunities in the railroad industry.
• This approach requires a passion for the subject matter and not just a focus on making money, as the speaker emphasizes the importance of falling in love with the process of finding opportunities.