For drafting practice, swim parallel to two teammates in one lane with one swimmer always slightly behind and then sprinting ahead on the last lap. For feeding, place gel packs in your swimsuits to practice fluid in-take during main sets. To replicate starts and finishes, sprint short distances (25's or 50's) together with two teammates in a lane starting at the same time.
6. Open Water Acclimatization
Just get in (the open water). Acclimatization is absolutely required to become familiar with the open water. Get used to cold water. Get used to rough water. Practice in the afternoon when it is windy, not in the morning when it is glassy calm.
Understand that you may hit jellyfish, see marine life, swim against wind chop, smell boat fumes, run into seaweed, and need to bodysurf in a race. Think of yourself as an aquatic adventurer; relish the experience, do not fear it.
7. Tactical Education
Study the dynamics of open water racing. Understand how packs get formed and why they take on certain shapes. Learn where and why packs get strung out and where you should tactically place yourself in the pack at different points during the race.
You need an arsenal of tools and tactics to perform well. Even though some swimmers have an innate navigational skill and a high tactical IQ, most athletes have to learn.
Knowing what these tools are is the first step. Knowing when and how to use these tools is the next step. Your tactical education—an oft-overlooked aspect of open water training—separates consistent winners from the rest of the pack.