Richard Feynman advises a former student to focus on solving simpler, more manageable problems rather than striving for grand, complex ones that may lead to frustration. He emphasizes the joy of success in addressing humble issues and encourages the student to redefine their self-worth based on their contributions to colleagues and the scientific community. Feynman shares his own experiences with various problems, highlighting that no issue is too small if it leads to genuine progress and understanding.