Hey, so sorry but the sigs aren't that good but for a first timer very good, If you want to improve you must go through tutorials, not copy them but learn techniques!!
Good sigs are those that have depth, render is blended well, the background has some unique effect, c4d are used, brushing is done, filters, gradients etc are used.
I just gave the above tips as I have experienced them myself, and thought maybe they are beneficial to you!!!
I would rate your sig 6/10 as a starter!!
Keep practising and eexperimenting, some day i'll rate you 10/10!! lol