I mean no offense to the designs posted - but a logo has to communicate something about the company. These are not just pretty pictures or symbols they are often the first contact you will have with your clients- so they need to be good.
Think about the image you would like to portray to your client if you were meeting them face to face - you would wear a suit no doubt and the examples of your work would be flawless - yes? your speech would be confident and you would enthuse confidence. A good logo will sum this up in a little collection of shapes and lines. And of course a logo will also include a bit of your personality - a colour or a bold line etc something abstract but intuitive.
I'd start from the beginning and brainstorm what your logo should communicate, then come up with a symbol for each of these, then combine the symbols in a meaningful way and you should find yourself a logo. 90% of the work should be spent coming up with ideas and trying them out - the last 10% is finishing off your logo.