yeah, it looks pretty simple to catch whats wrong...anyways from what I can remember...

The yellowing leafs on the edges looks like nut burn. The canoeing shapes of the 2nd and 3rd nodes looks like your over watering like a mo fo. One of the greatest mistakes of first time growers is that we get anxious and overwater and over nute. We do this thinking that the more we feed, the faster and better the weed. Not true.

I would say back off on the water. Take a metal or wooden long handled spoon and once a day, push the handle down in the soil, such as that as baking a cake, about 4 inches. pull handle out. if there is soil on the spoon, that mean that the soil 4 inches down is still wet. DONT WATER. only begin to water again when your handle comes up completely dry and without soil on it.

As for nutes, I burned my ONLY grow up by putting nutes to them too soon. I would wait for a week or two before putting the nutes to them. But dont take my advice too much to heart and wait for someone else who knows about nutes, comments on your post. Maybe ol' stinkyattic could help....if not him, maybe Zandor.