Try ebay. If tickets are still on sale, your chances of getting better seats for not too much more $ are pretty good. You can also try craigslist. As far as TM is concerned, unless you have those special programs that bump you to the front of the line, or a pre-sale password, getting tickets is luck. You can have other people try to get tickets as well. It could increase your chances.
Wait. Have tickets gone on sale yet? Even if they haven’t, the ebay suggestion still applies. Try right after tickets go on sale, or right before the show; you can get the best deals that way.
Are there still places in your area that sell tickets at retail stores? Almost no one stands in line anymore. It’s not convenient, but it’s could be a good way to get tickets.