Well, not sure what the first picture is related with I guess a 1-leg ninja holding a ninja star. The chibis are quite well done, except if it is naruto on the left, I think the shading is a bit too much, prefer it to be a bit more lighter. The last picture on the bottom is quite well done except due to the reason it is made with a marker, the shading on sakura hair is too much, but still
Well Done, Sensei! Also this are just my opinion, don't think I am a proffesional who gives out tips...
My only sensei is @Gaar