I did a duathlon on the shore of Lake Champlain a couple of years ago. It was a 5K run, 15-mile bike, 5K run.
Rocker gave the best advice: don't bother with a wetsuit.
No, seriously, dus are, in my humble opinion, tougher than tris. If I could offer any advice, it would be to train to run WAY longer than just the combined distance of the run legs, and to practice doing double runs, e.g., run twice in the same day. Bonus points if you practice doing double speed workouts occasionally.
I did well in my tri, but mostly because I had just come off 50K training. The second run leg still felt pretty short to me. I got (as always
) crushed in the bike leg, but actually made up distance against a few of the elites (!!) in the second run leg because I had mondo