I love doing pieces like this and sadly dont often get the opportunity to often. The general rule when doing sci-fi objects such as these is form equals function. Each part of the model should look like it should function even if in reality it cant.
When looking at the legs they look impossible to articulate (move) in any way, you dont need to follow any particular laws of physics just make them look like they can move and support the weight of the main body which currently they dont.
Before starting the next model do a quick image search and seek insperation from what others have done, dont copy but add your own interpretation to them and with a little patience you will amaze yourself, better to make one killer model a month than half a dozen crap ones. Remember modelling isnt a race take your time and sketch out some ideas even if you cant draw well. Make some notes on things you like about other models and what you would like to incorperate into your own model. ie make a plan.
As for the texturing I have to agree with the other guys but atleast you have tried, many guys dont bother. Hopefully by looking at some reference and seeing what other people have done you will see something more believable and will inspire you to do a better job.
Im not knocking what you have done, your doing well and keep it up. I`m just passing on some tips from an old hand thats been doing this stuff for far too long.
Good luck
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