diy wedding center pieces...

Please be honest. I'm not a crafty person what so ever so I'm having a hard time with this. We are on a low budget but I'm trying to make things look pretty and simple/classy...this is what I have for table center pieces so far. Our colors are black, white, gray with pops of yellow..I am thinking about adding yellow rose petals around the outside of these or adding small yellow flowers inside. Please be honest without being rude/harsh...I'm open to easy suggestions. Thank you!