Light should be 24 inches above them and at 50% power if it's a dimmable LED. HID's would be 3 to 4' above
Don't over water your plants, and don't over feed them. Don't water until the pots feel light, then water in enough to give them a drink, but not so the soil is saturated and heavy
At the stage those pictures show, they should be getting around 250 to 400ppm
Maintain your soil pH and keep it around 6.2