Which of the following tricks help travelers achieve upgrades?

• dressing sharp
  Veteran travelers have learned the tricks and tips to subtly increase the odds of a last-minute bump. Dress sharp, meet the manager, check in early, board late -- these are just a few of the time-tested strategies that separate the complimentary peanuts from the complimentary wine. How to Get Hotel and Airline Upgrades
• checking in early
  Veteran travelers have learned the tricks and tips to subtly increase the odds of a last-minute bump. Dress sharp, meet the manager, check in early, board late -- these are just a few of the time-tested strategies that separate the complimentary peanuts from the complimentary wine. How to Get Hotel and Airline Upgrades
• dressing sharp, checking in early and boarding late
  Veteran travelers have learned the tricks and tips to subtly increase the odds of a last-minute bump. Dress sharp, meet the manager, check in early, board late -- these are just a few of the time-tested strategies that separate the complimentary peanuts from the complimentary wine. How to Get Hotel and Airline Upgrades