Address the people you seek, and them only

The man who wins out and survives does so only because of superior science and strategy.

Remember the people you address are selfish, as we all are. They care nothing about your interests or profit. They seek service for themselves

On most lines, making a sale without making a convert does not count for much. Sales made by conviction - by advertising - are likely to bring permanent customers. People who buy through casual recommendations often do not stick

Changing people's habits is very expensive

This is no lazy mans field

Curiosity is one of the strongest human incentives