A good startline routine is important for a successful search. The startline should be reproducible so that your dog knows what is going to happen, yet it is important to keep it flexible to account for variations in searching conditions. When I start Iona on a search, I imagine that I am firing a rocket. I need to have the right power and the correct trajectory to get the job done.
Lets talk about power first. First you need to tell how much gas your dog has in the tank (arousal). I know that during trials, Iona generally has lower arousal (because she has been sleeping in the car for hours), however when we are training with friends in areas that she is familiar with, her arousal is higher. You can (and should) do plenty of things to change your dogs arousal before you walk to the startline so that they are not lagging or bubbling over. However, you can have an effect on the speed at which they explode into the search area by how you start them. I have found that by holding Iona back, she really shoots into the search area. I do this more for trials or when she is lagging. If she is already ramped up to an 11 or obviously is 100% ready to work and focused, I will sometimes just touch her harness or even do a walking start. Here is an example of a walking start. Check how I put some drag on the leash to make sure that she hits that first container.
As I alluded to above, it is important to send your dog in the correct direction. If you have the luxury of a wide start line, then be strategic about where you start and where you send your dog. I try to direct her to an object that is in the front of the search area. If she hits that object, she will often continue to work nicely. Often momentum just carries her away when I start her in an open area. This is why I started her to the R instead of straight ahead. In this search you can see me fumbling with my watch a bit, it is good to practice timing yourself before your searches if you plan on doing so during the trial.
Another interesting observation is that if Iona perceives that the search area is small, she will search smaller. However, she runs big when she thinks the search area is wide open. Check out the difference in these back to back searches. Watch her run past all the cars, what a nut!