Ok so first things first what kind of light is that? What temperature is it? What medium are you growing in? Apart from that in terms of corrections/tips I would say get some mylar or some kind of reflective sheeting and put it on the wall behind the plants. How often are you watering and is it just water? It might also help to get something over the seedlings so that the humidity can build up a bit, you don't want the plants to be constantly soaked but some humidity is definitely beneficial. You can get thermometers that measure both temperature and relative humidity so thats two birds with one stone as both of those things should be measured to make sure everything is fine. Your stems are also a bit stretchy so you might want to replant them, theres a thread in the newbie section that will show you how to replant heres the link -->
https://www.rollitup.org/t/replant-those-long-stretchy-stems-its-easy.429767/
The stems stretching means that either your light is insufficient or its too far away so knowing the wattage and stuff on the bulb would be good. also whats your light cycle? and how old are they? You could get a lot more help if you explained what you were doing first...