Start them early if growing from seed. If buying plants, get healthy ones from a reliable supplier. I got a fair number of serranos from a big box store plant, but the ones I grew from Redwood City Seeds got more than 5 times bigger with a lot more peppers. A bit different in the pepper world, but I used year old seeds that had been stored in my refrigerator and got great plants. http://userwebs.batnet.com/rwc-seed/
The rows are 4 feet apart...
Grow with plenty of light indoors - 16 hours a day until they get outdoors as soon as nights stay above 50. Fluorescent plant lights work OK, Halogen bulbs even better. The plants growing under 400W halogens were twice the size of those under a bank of florescents.
Don't let them get root bound. I repot 3 times before the plants go outside. If they stop growing, they are root bound.
Fertilize regularly (peppers love fish fertilizer - think Bassomatic, but it stinks.) I used Miracle Grow every week or two with good results.
Peppers don't like peat for some reason. I start in Miracle Grow organic potting soil, works well. Anything with peat will stunt the growth and produce a weak plant.
Be sure to harden off your plants - last year I threw them outside and lost a lot of the plants to sunburn, and weakened others. Like tomatoes, they do better if you gradually introduce them to outside, increasing their sun and temperature swing exposure over a week.
Peppers need calcium even more than tomatoes. Give them bone meal at least every other week or whenever your fertilize. I went through 12 pounds of it on 100 plants or so. I didn't do as religiously last year and lost a huge part of my crop to blossom end rot.
Peppers do well with alternating dry and wet spells. In pots, wait until the surface soil is dry to 1/8" or so. We were dry enough up here that I watered every day - by afternoon the plants were starting to wilt. They got 45 minutes a day. A longer dry period might result in hotter peppers, but I had a hard time seeing the plants look so weak the second day without water.
They don't want their roots wet, so well drained soil is good, but give them a layer of non peat organic matter to grow in that will hold some moisture.
Hope that helps you next year, Mike.
Gratuitous bragging how big my peppers are shots. My chubby hand is almost 5" across my fingers.
Duce D'Esagne, a sweet pepper that is red when ripe.
Anaheim or New Mexico (seedlings got mixed up)