Brumby,

1. Identify horses that are going to be in the $8-$20 range.
2. Do my own analysis to come up with what I consider the realistic chances of each horse identified in part 1 is (This bit is the "trade secret" part!) and work out my "good bet price". eg. If my analysis gives horse a 10% chance then I would look for a price of at least $11 (allowing a 10% margin - this margin varies depending on pool size, etc)
3. Few minutes before race see if any horses seem likely to start with a TAB price above my good bet price - these are the ones to watch
4. If possible watch selected horses behind barriers and as they are loaded
5. If selected horses still above my bet price AND they look OK as they go into barriers then place bet when all horses are loaded (ie. last few seconds before jump)