This is what I eat in a day prior to a platelet donation. For breakfast, I have a cup of black coffee and for lunch I'm making steak and some Brussel sprouts with napa cabbage stir fried in chili oil. When I first started donating platelets, I failed the iron test quite frequently but I've gotten a lot better at preparing by eating iron rich foods leading up to the donation I will always eat a steak the day before.
For dinner, I'm eating leftover steak with some steamed wontons in soy dipping sauce. And, after dinner I take a Flintstones vitamin with iron to get my levels up. On the day of the donation, I eat a steak and cheese omelet for breakfast using my roommate's leftover steak and I drink at least 3 glasses of water but I don't drink any coffee because that can dehydrate you. My appointment is set at 10:30 so I stop drinking by 9:30. You have to sit in a chair for 2-3 hours so you can't get up to use the restroom. Anyway, that's what I eat in a day leading up to a platelet donation. Also, today happens to be a pretty big milestone for me. I hit 4 gallons of platelets donated.