Take notes! If you sail different types of boats, take notes on how they are rigged (are the guys led inside or outside of the lifelines) and how the boat is sailed (do inside or outside jibes). Reading these notes before you go practice allows you to maximize your time on the water and not waste time re-learning how to sail the boat.
Stay calm. Don't yell. Yelling never accomplishes anything during a race.
The first priority of doing bow is to make sure the sails go up and down properly and that all the maneuvers are done correctly. Once you're comfortable with all the boat handling, then you can try to…
Think like the afterguard; try and anticipate the next move. Be aware of the other boats around you and the different possible scenarios at every intersection and mark rounding. Have a mental checklist always running through your head. For example, if you are coming into the top mark in a big right shift, there's a strong possibility you will jibe set to get on the favored jibe immediately. Be ready for it.
Develop your team within the team. The job of getting the sails up and down often falls on a specific portion of the crew. Make sure those sailors (bow, mid-bow, mast, pit, floater, etc.) are all on the same page and know what to do in any situation.
When calling the starting line, make sure the guys in the back know what your hand signals mean. Review these before the start just to be sure. Use a line sight if possible. This helps confirm where you are on the line. Also, understand the acceleration characteristics of your boat in the conditions in which you're sailing. Before each start, practice timed runs at the starting line so the whole team can feel how the boat will get up to speed.
Always have your spinnaker gear ready for the first set before the start. For example, if you're setting out of the front hatch, have the most probable spinnaker hooked up so you don't have to do it on the beat.
At the leeward mark, do as much cleanup as possible before the boat turns upwind. Get the spinnaker down the hatch and halyard back to the rig or taped at shrouds ASAP. Then hike. Minimize your time off the rail when cleaning up. If you have to put the gear in the pole and switch the topping lift to the correct side of the jib, do them both at the same time while you're off the rail. Try not to get off the rail multiple times. If you must go forward and clean, always ask the tactician when it's a good time to move.
Try other positions occasionally to get some idea of what maneuvers look like from further back in the boat. This will give you an understanding of what others are doing and going through in any given maneuver.
Debrief at the end of the day. Whether with the whole crew, just your bow team, or by yourself, go through the day and identify the good and bad and how things could have been done differently or more effective.
Stay fit! When not sailing, go to the gym and stay in shape. Running, stationary rowing, and core exercises are good basics. Try to incorporate a balance board or Bosu Ball into your workout.
The best way to get over jet lag is to get straight into the time zone of the regatta to which you're traveling. If you land at the event late morning or early afternoon, get checked into your hotel, but don't take a nap. Keep busy: Go to the boat and start working, or hit the hotel gym for a while. Power through the first afternoon, have a good dinner, and get some sleep. If I do this, I'm almost guaranteed to sleep through the night. If I take a nap when I arrive and then wake up for dinner, I usually find myself staring at the ceiling around 3 a.m. Having to wait four hours until breakfast opens is no way to start your first day of the event.
Controlling the spinnaker halyard during a drop is important. Once the bow team has the foot under control and there's no risk of putting it over the bow, ease the halyard slightly faster than they can pull it in. A good reference is the spinnaker should be draped over the lifeline as the bow is pulling it in, but not dragging in the water.
The primary piece of gear I have for every race is my harness. On it, I have a multitool, some tape, and maybe a spike if needed. For clothing, I always bring my UnderArmor or Nike Pro compression shorts and long sleeve top that I wear under the crew gear. If it's wet and cold, don't forget the Gore-tex socks!
The key to doing mid-bow or any other position where you are supporting another sailor is to try to be on the same page as the person you're backing up. Always put yourself in their position and think of what you'd do next. That way you are always there to help or cover without him or her having to say anything.