Welcome. I am in the same position as you. I am not really preparing for "long term" outages but mostly shorter term situations. Preparing for that is fairly simple. Each time to go to the store, buy a little extra of items that have very long shelf life. I get an extra bag of dried bean, extra bag of pasta, extra can or two of canned veggies or meats. Just put aside the extra items in a separate location. Every so often, I will pull items from this area and use them and replace with fresh items. Brent is a big believer in Water filter (rightfully so). In my case, I have a well which I run the water through a filter. I keep a few extra filters sitting around and when I change the filter, I use one of the spare and replace it with a fresh. As with everything else, READ what the filter is good for and spend the extra money to get a good one and not a cheap filter. I also keep several 5 gallon cans of gas around for use around the house. I always use Ethanol Free, Treated gas. As with everything else, I rotate. Using the oldest and replacing with fresh.
Don't forget the other items that you don't necessarily use everyday and add to your supplies. Batteries, candles (when is the last you bought candles), matches, lighters, charcoal, etc. Don't need to get all at once, just when in the store, pick up on or two and quickly, you will be set.
Generally, for short term, that is all you really need to do. Just keep extra supplies around. You may find it easier to keep a list of what you "stockpile" just to make sure you keep it rotated.