Find what works for you. I promote individualism when it comes to pitching and routine as long as it works withing reason. I have one starter who throws a pen at around 70% the day before he pitches. One guy throws a full pen two days before and a 50 foot/60% pen the day before just to get feel for pitches. One guy who starts in the outfield throws early in the week, two days after he pitches with a 50 ft/60% the day before. The other three starters throw full pens two days before a start and play catch the day before.
It works for each guy, and pitching is such a psychological battle that the most important thing is getting into a routine for comfort. As far as eating, again, find what works best for you and what makes you feel good and comfortable the next day. I always recomend getting a good nights sleep without oversleeping so that you don't feel "groggy" out there.
If there is familiarity with the opponent, go over how you plan on getting guys out and how you are going to attack guy's weaknesses. Who you don't want to beat you, etc.