I take it you are not a cross-dresser.
Food-wise you should avoid fat and celluose - bacon and beans. Reduce carbohydrates and maintain a proper water balance.
Even at low cabin altitudes the atmosphere is drier than on the ground and you will dehydrate. You must therefore drink plenty of water but as CC you will not be able to pop to the loo every 5 minutes, hence the balance.
Your job is your feet or vica versa. You will be on your feet for much of the time, even when not pushing or pulling a trolley uphill for 6000 miles. Good, well fitting shoes will be essential. I can't comment on clothing and shall leave that to others other than to say your uniform might not be what you would chose for comfort.