you could try making the basic shape out of a flat poly (looks like thats what you are doing) then extrude it so it has depth. then add the screws and bits as seperate pieces. use the split poly tool to add further detail.

one thing to keep in mind is to try and keep it as simple as possible. there are alot of divisions you dont really need in your model.

another tip uv map it before you put in a ton of detail in. its easier to pull fewer uvs in the uv window.

good start and good luck!