Ironman Hawaii
Start position
Start on the left side of the start line.This is for 3 reasons:As the photo below shows (click to enlarge), the buoys are not always in a straight line. Thus people maybe 10m from the right end of the start line, who swim directly to the turnaround buoy, will go right by the first buoy. Everyone starting to their right will be in the way because unlike in other triathlons, at Kona you're not allowed to swim to the right of the marker buoys. Kayaks will stop you. Thus things are very tight very close to the first few buoys.
People don't swim in straight lines. Even from the middle of the start line people tend to swim towards the buoys very early, rather than taking a direct line to the turnaround buoy. They'll drag you with them.
The start line is slightly less chaotic further to the left.
Pre-travel acclimatization
The average temperature high in NJ in October is 66 degrees. In Kona it's 87 degrees.
Complete heat acclimatization requires up to 14 days (citation here) but, per that citation and others (eg, here) most of our acclimatization is obtained within a week. Thus, there's little value in running on the treadmill in winter gear three weeks before the race. I'll do a few workouts in extra clothing in the week before flying out, in order to ease the first few, longer workouts on the Big Island.
Once in Hawaii, many athletes will avoid air conditioning until after the race.
Electrolyte Loss
More of an issue in Kona than other Ironmans. I haven't yet read a more useful article on the math of electrolyte loss than this one: (Click here)
Transition Tips
There are plenty of these on the transition page.
Bike configuration
Disk wheels aren't allowed in Kona. A deep rear or Tri spoke is generally considered the best rear wheel option regardless of the crosswinds. On the front the fastest wheels will generally also be the hardest to handle in the crosswinds. Brave or skilled cyclists will often use a Tri spoke on the front, such as a Hed 3 or a deep dish wheel like a Zipp 808. I tend to use a Zipp 404 though in 2001 even that wheel was very tough to handle in the notorious crosswinds of that year.
Here are the advantages of various combinations of wheels OVER A 40KM TIME-TRIAL, assuming no loss due to bike-handling problems:
(The above image is externally sourced and hosted)
Here are a couple of photos of my bike in Kona 2009, note that I'm prepared for 2 flats (most people prepare for only one). Despite carrying quite a lot of stuff, everything is stored out of the clean air, and the bottles are on the seattube/downtube which tends to already be very turbulent and moving forwards. One bottle horizontally placed between the aerobars is a more aerodynamic option. Behind-the-seat bottles are bad for a multitude of reasons, mainly safety, aerodynamics and inconvenience.
Here's the 2010 configuration, one water bottle now lies horizontally between the aerobars: