Eyes down, earbuds in, mouth shut, mind your own business — especially on business trips. If you're a frequent business traveler like me, here are 10 lessons I've learned to make travel easier, cheaper and less painful:1. Related: Here's How Entrepreneurs Can Save on Business Trips2. Avoid airline and hotel travel cardsAirline and hotel credit cards aren't worth it. Do not wait in rental car linesThank God we don't live in the days of our parents, when renting a car required sixteen forms of identification and a strip search.