Elbow and knees are some godd finishes. Kneeing in the stomach or floating ribs are effectives techniques, also elbowing them in the face. Me personally I would just finish them off with a good punch to the face or somach.
I dont get these different color gi just give me a black or white gi and I'm fine. The only time I alter from my school uniform is when I go in on days to train with my weapons ( and the only thing i change is I have a read bottom on instead of a black)