After suffering through Harvey the past 2 weeks i can tell you a couple things.
1-Go buy 10 gas cans. There are some stations around here that are out or run out almost daily
2-Buy ice. You will run out of ice i promise and you can save a lot of food (and have ice for drings)
3-Buy a small generator-YOu cant run your house on it but you can power up your fridge every couple days and do laundry.
4-Buy food that takes longer to go bad. PB&J, oatmeal, cereal, etc....Mostly stuff you dont have to cook.
5-Fill up your propane tanks and have spares. You can always boil water with a propane burner or use your gas grill.
6-If you are evacuating, do it now. The roads out of Houston had traffic jams for miles. When hurricane Ike hit a few years ago, there were 200,000 people that had to go through it in their cars on the side of the highway because they ran out of gas.
May God bless each of you as i know what you will be going through.