Hey, this is a really good model for a noob . One thing i would do.. like others have said.. is add some DOF... also, your shaders you have added would be better off maybe as something else. One thing too.. you may want to add a smooth to different parts of your model. Just small details could make a world of a difference . You see your exaustion pipe for example? If you put some kinda bevel in where the next pipe comes out of it.. it would look more realistic.. but when you just have it coming out of the polys, it looks like it is a model.. as nothing is that sharp. Im talking about some stuff thats not really easy to do.. but for a first project, really nice job.. i would personally continue on with another model, it is a great way to learn a LOT about maya and fast . Quick small models that contain challenging elements that are in and out within a week . When you get to big things you get a lot of repetition. Anyways, great first model!

One other thing, i see that your model looks pixelated.. are you sure your quality is on highest? I dont think it is.. as it does look a bit pixelated in areas . If thats the case, re - render it out and post again . Keep up the great work.