Seedlings that are white, long, leggy, and weak-looking are not getting enough light and need to be moved promptly. The best locations are sheltered areas outside on sunny decks and patios or inside greenhouses and cold frames. If you must start your seeds indoors and you rely on artificial light, place the lights very close to your propagation trays. If you are using fluorescent light fixtures place them within several inches of the top of the soil surface. This may seem too close, but it is not.
Most seeds germinate better when the soil is warm.
In some cases it may be possible to heat the air in the area where you are starting seeds, but often it is more sensible to use a seed tray heater to heat the soil. Seed tray heaters will improve your results significantly, especially with tomatoes, peppers, and eggplants. Don't cover small seeds with soil. For most perennials, vegetables, flowers, and herbs we place the seeds on the soil surface and press lightly with our thumb to insure good contact between the seed and the soil. That is all.