Seems a little over contrasted to me and all the colours are way over saturated. Your lighting needs work as you have a light source but the lighting stays the same taking all ambiance out of the piece. Your light source itself seems to be coming from a slightly off angle. The Renders entire right side is brighter implying a slightly lower angle than where it's at at the moment. The effects themselves are ok but they are few and far apart which makes for an empty sig. My recommendation on text is just to leave it out until you really know what you're doing with it as Text is usually a make or break affair. Only a few people on here have really mastered it and when done wrong it can make the sig look tacky. In general you just need to work on each different aspect of your Sigs. My advice would be work on each individually on sigs and then put what you learnt from your previous sig into the next one. Maybe don't even change the render just change what you're doing with it. Tutorials are another way to improve different aspects of your designs. Right now i would suggest concerntrating on lighting and colour use(IE saturation, colour choice etc)
Sorry if that sounded a little brutal, but usually brutal is the best way to get across what you think in CNC