I've been doing food preps for a couple of decades now (e.g. I have 5 6-gallon buckets with wheat berries in it for bread).
Things to remember:
1. Eat what you store and store what you eat. If you do not regularly eat MREs you will be sick as a dog when you try to subsist on them. Not to mention constipated (or so I hear).
2. Prep canned goods and have MULTIPLE can openers (the dollar store kind as cheap as they are, not the milsurp, those are a pain). And refer to #1
3. Start using a food dehydrator to dry food for later. I have a couple of jars of dried corn I put up some years back. Fruit dries nicely too. Refer to #1
4. Use a vacuum sealer whenever possible. The enemies of food are heat, light, air and water. I vacuum seal stuff (no air), put it in the freezer (no heat, light or water). We buy in bulk and on sale, then put it up. And yes I have a genset, but gas only lasts so long.
5. Commercial freeze-dried foods (Mountain House, et al.): I have some, have tried of few of them, they're not bad. They are expensive and getting harder to come by as you're not the only one thinking about this stuff.
Costco for example is now offering pallets of "emergency" food. I know nothing about the brand they are selling but have read other folks who have gone this route in the past.