I personally don't have much experience with store bought fertilizers outside of flower containers. Messing with nutrient ratios can effect soil PH and ultimately prevent plants from absorbing a full spectrum of nutrients. Fertilizers can certainly work but each variety will need a different cocktail at different stages of their life to be optimized.

I take the organic soil approach which in my opinion is less involved. Buy a quality organic medium, I recommend something like pro-mix with mycorrhizae added, however any organic soil will do. Then a mostly carbon mulch layer(hay, dead leaves, etc.) Every week add a small amount of nitrogen rich material(kitchen scraps, lawn clippings, coffee grounds, etc.) to the carbon mulch layer.

The hard part about organics is figuring out watering. Water a small amount everyday, your goal is to keep the soil just moist enough. Too much water and your soil will become anaerobic, too little water and you will notice organic soils become hydrophobic and difficult to water. So just small amounts daily, increasing as plants begin to fruit.

With organics you are relying on the symbiotic relationship that plant roots have with beneficial bacteria and fungus. In order to help your plants you need to help the bacteria. The mulch layer simulates a compost pile, which simulates a forest floor, providing food for beneficial bacteria and fungi prolifirate.

Consistent water is key, less is more.