Excellent advice and good point about the N deficiency. Someone needs to write a FAQ, because with every crop of newbies, this topic comes up again, and again, and again.......The fan leaves are nessesary, they absorb light, which buds don't do for themselves, and which is needed for chlorophyll production. If you prune a few it's ok, a good rule if thumb is to cut off completely only leaves that are 50% or more dead. (although I'm a really heavy pruner) If bottom fan leaves are yellowing but the tops are good it's probably a nitrogen diffeciency. So even though it seems like they're blocking light, they're actually there to provide it.