Ron and Hogjowl nailed the two big pillars: Performance and Presence. You have to do good work, and you have to remind them you exist.
But if we're teaching newbies, there are three more pillars that cement a customer for life:
3. Authority (Education) A lot of guys can clean a carpet. But very few take the time to educate the client on what they have. When you walk into a home and explain why you’re using a specific low-moisture process on their "waterproof" laminate because the core is actually wood-based and risk-prone, you stop being a commodity. You become a consultant. They might find someone cheaper, but they won't find someone who cares enough to know the science.
4. The "One-Stop" Convenience Most homeowners don't want a Rolodex full of specialists; they want one guy they trust to handle everything. If you only do carpet, you’re forcing them to cheat on you for their tile, their countertops, their upholstery, or their showers. The more problems you can solve under one roof, the harder it is for them to leave you. Be the solution for all their surfaces.
5. Community Roots People want to hire a neighbor, not a faceless service. Be the guy who knows the best plumber or electrician in town. Be the business they see cleaning up the local park, supporting the church, or helping out at the battered women’s shelter. When you are tied to the community through charity and service, firing you feels like firing a friend.
The Bottom Line: Make yourself indispensable. Be the expert, be the one-stop shop, and be a pillar of the community. Do that, and they’ll never look anywhere else.
Finally, and if by the grace of God, the family dog and the teenagers like you, raise your prices, you're a Unicorn!