The outline on the shirt is easily the biggest problem, though I'm not sure how to improve it.
I've never really understood how to outline white.
Apart from that, you should probably work on your shading. Try and stay away from one pixel shadows that follow the outline- try and think about it in terms of geometry.
I've roughly sketched out how I would construct the trousers in 3D- you can see where I've tried to indicate the crease-line down the centre of each leg, which terminate at the bottom in a sort of tent shape. Again, stay away from the outline, and start thinking in bigger shapes when you're shading, really.
Excuse the cigar and such in the second image, and instead focus on the trousers. Hopefully you'll see what I mean when you examine them. It's worth mentioning that I brought the crotch down a bit, you had it uncomfortably high originally.
I'm no artist, so this might be really terrible advice. Sorry!
Terminals upon which the unravelling of a mystery could begin. These could really use a table to sit on.
And here's a few older things I've done for Space Station 13.
The frame on that furnace isn't mine, but the fire animation is.
Thanks for the feedback Pete! the outline of the shirt is a right bugger for sure! thanks for putting out the innards of the trousers I had not put any thought to those but now I look at them its clear that they need to not be straight and have the crotch lowered, think of the poor guys prostate! I have been trying to work on my shading so he will be my next attempt at improving my shading