ok, a few more tips.
Broadly speaking I limit my bulk purchases only to what i can use up in 3-6 months (it varies somewhat based on the ingredient).
Avoid the temptation to buy a multi-year supply of anything; it will take up storage space and most things won't taste as good (or will spoil completely).
For dried goods, sunlight and moisture are the enemies. Combat them by storing in air-tight containers in a pantry or cupboard. Glass "mason" jars are cheap and very useful (though they do break if you drop them or have small children). Good alternatives are lexan containers with gaskets (available online and at restaurant supply stores). large zip-lock bags can also work well but make sure it is well sealed. Rice, pasta (dried), beans, lentils, oats, flours etc can all be stored this way.
Most of the powders (nutrient powders, gatoraid, country-time lemonaid, etc) come in containers that aren't very good at keeping moisture out once opened. Transfer them (I worked on a sail-boat and our lemonaid mix would turn into a brick after a few weeks if we didn't).
Ground spices should be used within ~1 month. Whole spices will last 3-6 months before they start loosing flavor. Buy whole spices and grind small amounts yourself. Certain spices (pepper, nutmeg) is only at its best when freshly ground. Again, light is the enemy.
Freeze and animal protein you don't plan on cooking in 2 days. Freezer-bags/foodsaver bags help, but it's also important that it stays frozen and doesn't freeze-thaw-freeze-thaw.