i've recently solo'd but heres my advice to you, hope it helps

pick 1-3 students who stand out as people in it for the long run and concentrate most on them. You could use your own trainer to help students, use a powered glider, that way, they can't do loops, rolls ect without snapping the wings (or damaging them in osme way). That way it'll force them to get more precise, i have one of these and i practise loads staying in the circuit ect, i can fly an approach 4 feet from my head now in complete confidence . Before some peeps critisise me though, i do it when no one else is around or away from the pits and other flyers.

Also, take a break from instructing, dont force yourself to do something your not particuarly happy with right now, its YOUR hobby so do what YOU want to do

just my 1.5p