Find out the on-sale date for tickets as far in advance as possible. Be very aware of the announced process to sell tickets, including the time and place where tickets will be sold, as well as any limits to the number of tickets you can purchase. Find out about any options to buy tickets before they go to the general public, like through season ticket subscriptions and fan club memberships.
Enter presales for tickets. Enroll friends and family members so they can enter the ticket presales, too. If an event sells out and your friends and family also get tickets, they will have no problem reselling them on websites like Craigslist and StubHub.
Call the ticket outlet 15 to 30 minutes before tickets go on sale. Ask for a live operator, and ask her to check availability for events other than the one which is about to go on sale. Then, when the on-sale time arrives, you will already have a direct connection to the ticket outlet. Being in direct contact with an operator before the tickets go on sale provides the most direct access to the ticketing system, which is sometimes a better option than the website-based system available to the public. Ask for the tickets and have your credit card ready to purchase them.
Go to the ticket outlet website while on the phone with an operator, and reload the page until the tickets go on sale. If you have better luck maneuvering through the purchasing process online, use your credit card to purchase tickets that way instead of over the phone.
Check back on the ticket outlet website closer to the date of the sold-out event if you are unsuccessful in getting tickets and don't want to pay above face value by purchasing tickets from a broker. There are sometimes "drops" in which tickets that had been set aside for various reasons are released for sale.