Need constructive criticism

Just started to make my own sigs and would like some constructive criticism on how i can improve my work.

My work in couple of hours:

 

should of had render on no2 closer... looks plain,simple effects, aim for deep orange on number 2 would suit it alot more!

 

Work more on depth and lightning. Atm the sig looks plain and booring. Try reading some more tutorials.

 

looks cool to me. Simple, but cool.

Not my type of pictures though

 

in my opinion, the text that u chose is not cool looking. perhaps change the text to something not ordinary.

 

First one is nice i think