Apply for a travel rewards credit card. Use a website like CreditCards.com to compare different travel rewards cards. Factor in how often you travel and how much you plan to spend on the card, when deciding on the best option for you.
Sign up for the frequent flyer program associated with the airline you plan to fly. Typically this process takes just a few minutes and involves visiting the airline's website and filling out a short form. You'll be assigned a frequent flyer member number which you'll need to use each time you book a flight. If you apply for a specific airline's credit card, you need to become a member of their frequent flyer program in order to use the points accrued on the card.
Use your airline miles credit card to accrue points. Every card is different, but usually programs give users one point or mile for every dollar spent. If you're looking to gain enough points for an upgrade, consider using your airline rewards card as your primary credit card in order to accrue the required number of points.
Check your credit card's policy on using airline rewards points for upgrades. Some airlines allow travelers to use miles to upgrade to one class above the purchased ticket. If you're looking to upgrade from coach to first class, you may need to use a combination of points and cash to receive your desired upgrade, depending on the airline.
Book your ticket depending on the method required by your credit card's rewards program. Some credit card companies, allow users to transfer their points to an airline frequent flyer program; the traveler then books directly through the airline and uses their miles for an upgrade.
Once your ticket is booked, you will need to request an upgrade either online or via phone, depending on the airline's policy. Double check that you have enough mileage points to complete the upgrade.