#1 (superficial one) - Seems to be oversharpened in places and lighting seems to be too intense, there is no focal as everything is so bright, try some vignetting. I'm not even sure what's going on but there is the use of clipping masks that I can ascertain lol. Decent but you can do better imo.
#2 - Oversharpened in places aswell. I'm not that great at c4d pieces so I can't really comment further. The text is integrated decently though I think
#3 - I'm not a fan of black/white pieces but that's just me. The focal is oversharpened and the rest is so dark that it is hard to ascertain the other details.
#4 - It would be nice if the change to black/white was gradual instead of as abrupt as it is.
#5 - Not much I can say, pretty sexy except the text looks out of place
#6 - Another nice piece. Are the chains done in c4d aswell? Is the background a stock or what? Text looks out of place though.
#7 - Nice use of tech brushes. Fade to black on sides could do with a bit of a touch up though, looks a bit messy. Monitor on the left looks a bit low quality.
Overall I'm being quite critical but it's a must for you to improve your game (That's already very good mind you). You're still ahead of me by quite a bit though haha. I'll post some of the shit I've done for school on saturday man ~.^