Growing Lettuce Indoors

can anybody give me some advice on how to grow it its iceberg lettuce

the first one is my grow box i have two cfls one 20 watt and one 25 watt and a hepa filter rig to where it blows through two paper tubes into the box to keep the lights cool and to make the plants strong and in the second pic is my best plants and the third is my last three which don't seem to be doing that good