Buy guns - more than you think you, your wife, your kids, your neighbors, and your dogs could possibly need.
[Do NOT get your cat a gun!]
Buy ammo - a lot more than you think you could possibly need, then triple that amount.
Buy accessories - consider lasers, new optics, etc.; find holsters you like (good luck on that one) and then make sure you have safe and convenient access to self defense when walking, driving, at home, etc.
Get lots of practice - range time should include taking the safety off every time you pick up your firearm if you carry/store with the safety on.