Remember that seeds planted indoors will grow long and lanky if they are kept too warm or too dark. They should be planted 6 weeks before the frost date. This eliminates thinning and potting. It is hard, heavy and carries diseases. I use Pro Mix, but any well drained sterile seed starting mix will do.
Some seeds germinate quicker if the hard shell is nicked.
Morning glories, moon flowers, and sweet peas even respond to an overnight soaking. Remember seeds should be kept moist. If that first tiny hair root dries, leaves will not emerge. For healthy plants, have sterile conditions, good air circulation and space between plants. Good light, with sunniest southern exposure or supplemental lights left on for up to 18 hours a day will insure sturdy plants.