Good base! Though the next step would to start adding a bit more details to the overall design. Perhaps a few engine greebles and unique shapes. You may be trying to stick with the more realistic look so the unique shapes part may not be the thing you were going for. Again, nice start, I hope you expand a little more on this!
Nice! Quite good for a first :-) I like those armors you used as bullet-proof vests and the design of the vehicle looks cool. It needs a bit of work though, but i'm sure you'll make some really great MOCs when you are more familiar with LDD ;-)