Congratulations on this new project. I suggest a box of organic fertilizer. Plants in pots will definitely leach all nutrients out of that little bit of soil pretty quickly. A blend of naturally occurring nutrients, mixed in the right proportions for vegetables, will produce healthier plants, more and better fruit, fewer bug problems, and produce with a higher level of nutrients. Don't use MiracleGro anything. It's all synthetic. Not what you want.
I'm not sure what pests you might encounter where you are with the peppers. For the tomatoes, be on the lookout for tomato hornworms. If your plants start to look like something's eating them quickly, check the leaves thoroughly. They're hard to see at first because their coloration blends so well with the plants, but once you see them, you can't miss them. They're big, they're green, they've got horn-like projections, and they're creepy. You control them the old fashioned way: squish 'em.
It's more likely you'll get plant diseases than bugs. You might want to pick up a photo guide to help you diagnose nutrient deficiencies and diseases. These can be very helpful. Organic Gardening magazine puts one out, and I'm sure there'll be things online to help you.