clear website browser history in any/all browser you are going to use.
log on to your ticketmaster account FIRST..then go find the event page (you can do this 10 minutes earlier).
refresh one site, refresh the other...
keep your ticket request reasonable. Don't go for 6 tickets when you really only need 2 (or even 1). The fewer you look for the better. If you do get in..put in GA in one search, and seats in the other.