My advice for while you're racing (not what to pack etc) is:

As a mid fleeter (like me) you need to be very conscious of clean wind, particularly coming out of the bottom mark. There is always a temptation to sheet on and follow everyone out to the right hand side of the course and suck their shitty wind all the way to the lay line. If the right hand side is favoured and if you don't come out of the mark higher than the boats in front you consider a couple of quick tacks ie get to speed tack, get to speed tack. This should mean you'll have clean air all the way to the lay line and in a big fleet it can allow you to pass a lot of boats.

So I guess my pre regatta advice is to practice bottom mark roundings and sort out your [censored] so you can hit the pin (not physically) every time and come out high and fast.