The main key is light intensity. Commercial growers have the benefit of some serious hardware. They normally use a combination of high pressure sodium and metal halide lamps that put out enough wattage you could get a tan under them. There's no practical way a small time gardener can afford to put that much lighting over a small grow table. Also, they use big fans, so there's always a slight breeze in the greenhouse - plants respond to it by thickening up the stem, so they don't wave around so much.
I have 2 (2'x4') tables for starting seeds - each one has two 4' fluorescent fixtures (54 watt T5 high output) hanging over them. Even with that much light hanging over them, my seedlings could always use more. I like the fluorescent lights, because they are a lot more energy efficient and don't put out as much heat as other lamps. That way, you can put them really close to the plant leaf without scorching them, and they're not a fire hazard, if they fall over. My folks had a cat knock over an incandescent grow lamp down, and it would have caught the carpet on fire, if someone hadn't been there to smell the smoke. Ive been leery of those darn things ever since. I also have an oscillating fan set up, so it blows on my plants all day long. Everything is run through a couple generic timers, so it all runs 8 hours a day, without me having to turn it all on and off.
My biggest problem last year was some warm weather in March - I got the itch really bad, and planted everything too early. The peppers were OK, but the tomatoes germinated in only 5 days. Then, I had late frosts outside, so I couldn't get them out to harden off until May. By that time, they were almost 20" tall and still in the 3" pots! It looked like a disaster, but they still did well, once I finally got them out in the garden.
As far as fertilizer goes, you might get away with a little Phosphorous and Potassium, and some micro nutrients. Whatever you do, don't feed them any Nitrogen. Nitrogen will seriously compound the problem you're trying to avoid. Its probably best to wait until they're out in the garden to put any fertilizer on them, if any at all.