Editing and Redrafting Woes

Struggling a bit. Well, in the sense that I'm redrafting a story and editing it and adding lots of words and good things like that, and have been getting really into it, but in trying to make characters better having the problem that I have far too many chracters -  but then it's a school. It has to have all these characters. How do I balance that?

Maybe it's that I need more plot. I don't know.

And I keep thinking, 'ooh I should put a scene in in this classroom or where this happens', but then I'm very concious of scenes needing to further the plot. You know what I mean?

Does anyone else struggle with this? 

Any advice?

Other than that things are going well - despite my worries about this draft, I'm loving editing this story. And I handed my poems and essay in (yay!). Things are looking good this term. Busy but good.