Big fleet, heavy air- Be on the line around 4-3 min. Luff, and make sure you have a large space, and there's more room to leeward of you than windward. Start sheeting in around 15, keep sheeting in until 10. By 10-7, you should be at full race speed. at 5-4, I heel the boat to leeward, and get alittle extra speed. Cross the line at 1-0.
Big fleet, light air. I've gotten some of my best start and results by being over at the 1, and having to come around the rc boat. Just make sure you momentum and speed. I normally sheet in around 30, to get the boat moving. Again, heel to leeward to get some extra speed, then go for it at 3-2.
You need to practice trying to stay still in a way that you can accellerate out from. In club racing the line may be quiet enough to just sail a timed run but once you get any quality/large fleet you won't find the room coming in late so need to pick your spot early and sit there.
Conditions will effect how close you sit to the line (big waves/wind strength etc)
The Startline DVD is quite good at explaining various techniques.
Start lines are actually quite approachable but just as with dating, some people are more comfortable with the multiple starts with multiple other people.
In Austin we schedule a Wednesday speed starting event for new starters. late starters, starters lacking confidence and those starters who are getting back into the starting process.
We schedule three minute starts with as many as 30 participants. Sailors spend three minutes with each start and then move on. If a sailors is particularly happy wth one of the starts that sailor often schedules to meet at the after the multiple start event and spend lots of time chatting about that start and how to make it work over the long term.
You can red about starting. You can talk about starting. But the only real way to get a good relationship going with a starting line is to meet up with as many starting lines as possible and be yourself around them.