Hi Nong!
#28 - Please change the position of the rings so that it appears to be facing foward and side rings curving back.
#29 is getting there but rather than have it tilted back they would prefer to see the 360 straight on and sides curving back. Please let me know if you need more clarification.
#57 - please contour the lines where they cross. Also please add a little more texture so that it appears more 3-D like. Thank you.