Brand new gardener here. I keep trying to start basil from seed (have tried maybe three or four times) and I'm clearly doing something wrong.
1. Put herb soil from Home Depot in a pot and put a pretty heavy concentration of seeds in the soil. Pot stayed outside in the shade (summer in Seattle) and was watered about once a day. Basil sprouted just fine, got to about 1.5 inches high and then stopped growing and died.
2. Started basic in egg cartons outside, waited for sprouts, then gently separated the sprouts and replanted in a pot. Watered about every other day. Basil got to about 1.5 inches high and stopped growing and died.
3. Planted seeds in a pot with sandy soil underneath and herb soil on top, planted seeds. Kept pot indoors by the window (was hitting autumn, so temp dropped), watered every other day. Basil got to... well, you get the idea. I had two pots of cilantro that did just fine with this setup.
4. Bought two adult basil plants from Trader Joe's and ate them up. They were delicious.
I'm clearly missing something important. Any suggestions, or basic herb growing how-tos?
 Oh, and I now have my own house so pots are not a necessity anymore. If you've got tips for proper outdoor planting that would be great too! I don't think I'm too close to planting season in Seattle yet though.