Step 1: Take a small notebook, and for the next week, record every single item you use. Whether it’s a bottle of water, some toilet paper, or food. Record the type of item and the quantity. At the end of the week, look at your list and extrapolate for one month, two months, a year – whatever you want. Then go and buy that. That should be a start (make sure they’re not perishables).
Step 2: Start thinking about the stuff you DON’T use but MIGHT NEED, such as an extensive first aid kit, a first aid and survival manual, radio and other communications, etc.
Step 3: Finally, when your current “bug in location” is setup decently well, with at least a few weeks of food and water (and preferably some barter goods like Bic lighters), then think about a bug-out bag. For this, look first at what backpackers bring with them on trips. Then also look at what bushcrafters bring. Finally, add a few emergency survival type items (for example, backpackers frequently have no serious first aid or trauma kits). Then walk around with your backpack and actually try to live out of it for a few days. You’ll probably realize it’s too heavy and start ditching half the stuff. Look at Ultralight backpackers for some ideas on lightening the load.
Step 4: Create a bug-out location, preferably close enough to walk (200 miles or less) but far enough away that it shouldn’t be affected by local natural disasters. Then stock said bug-out location with important items, start a vegetable garden or collect seeds for future planting, etc.. A lot of people (me included) start thinking about bug-out bags, without realizing that the purpose of a bug-out bag is to get you to somewhere, not to become a refugee (although that is also a possibility to prepare for).
Step 5: Start acquiring skills. Concentrating too much on gear can cost you your life if you find yourself without some essential item. But skills weigh nothing and you can take them everywhere with you. Take a survival or bushcraft course nearby, take a (serious, such as a wilderness) first aid course. Most importantly, practice your skills regularly enough that you don’t forget them. And remember that virtually everything has been documented and explained on Youtube. You could easily search for “How to find tinder fungus” or “How to make charcloth” and get dozens of videos.
Step 6: Think about your EDC, or Every-Day Carry. This is the stuff you have in your pockets, at all times. Unfortunately, disaster may strike when you’re not at home, or even if you’re out of town, and hence without access to the majority of your preps. This is why it’s a good idea to carry a mini survival kit or just some useful items (such as a flashlight and a multi-tool) with you at all times. Additionally, think about creating a GHB, or Get Home Bag, which is a fairly small pack with some vital necessities to get you home, like water, a little food, a self-defense item, etc.
I hope this helps 😉