If you're not familiar with this method I'll explain it in layman's terms. You put other plants next to your fruits and veggies to help them grow and keep diseases and pest away. Here are a few examples of "companions" to increase your success.
Dill- plant with cabbage and brussel sprouts.
Sweet Alyssum- plant with broccoli and potatoes.
Gazanias- plant with peppers.
Nasturtiums- plant with corn, beans, squash, and cucumbers.
Marigolds- plant with kale, lettuce, and parsley.
Cosmos- general.
Keep in mind you want to follow a guide for this so you're not placing plants that will be competing for the same nutrients.
From a prepping stand point this can also be used to hide some of your veggies in plain sight.
Here's a pdf to help explain a little more, but you can also pick up some good books at a public library to help you out.
http://www.hpfb.org/uploads/companionplanting.pdfAnd here's a chart for basic planting (vegetables, fruits, and herbs) that would be good to print, laminate, and keep with your seeds.
http://farmtopreschool.org/pdf/2.3_CompanionPlanting_Chart.pdfIf anyone ever has any gardening questions feel free to PM me.