There are no secret tips or magic potions to get decent seats, just some things we've figured out by using presale codes or  making regular onsale ticket purchases for awhile now.
Here is a list of ideas:
Join the fanclub. Access to tickets goes first to members.
Register credit card at ticketmaster beforehand. In case pull good seats, you wouldn't want to lose them if get timed out.
Be early at ticketing window. And don't leave if the presale window doesn't open at the said time - there have been delays up to an hour and those that stay get less competition as many said 'the heck with this'
Do some fishing of tickets. Sometimes the first pull is nosebleeds, while 10 minutes later you find row1. Go figure. For extremely hot ( read that as Hannah Montana, Bon Jovi ) - we wouldn't fish too much
Be patient. There are often public presales such as AEG/ Radio/ or Venue presale codes madea available.
Watch for second shows. If the tour has any room, additional dates might be added should sellouts occur.
If resorting to re-sellers of tickets. Wait and wait - why rush? Prices will drop as near the show date and re-sellers want to unload tickets.

Probably skipped tons - but wrote this up fast. Might come back to edit- or not. Oh, and if you like please vote 'yes' as we like the little icon eBay gave us.
Have a nice day.