3 easy steps (Score 1)

Step 1: dog with a loud bark. Not even a guard dog, or a big dog, just a dog with a good bark and a predilection to use it. Step 2: Glock 19, the easiest-shooting, multiple-use handgun on the market. Concealed carry or home defense, it'll have you covered. Step 3(this can be step 2, also, depends on your exposure to firearms): Take a firearms and self defense training course. Hell, even if you don't do either of the suggestions above, take a defense course. You'll meet like-minded people who can help you with home security ideas.