So far as the first one goes it's a bit flat and a couple of simple things you could do is blow out the white background (levels adjustment) and add some contrast (curves adjustment). That would give you something like this (before and after):
The curves adjustment has added colour saturation too. I would also be tempted to make a slight adjustment to the skin colour using a selective colour adjustment (not included above) but that may or may not be available in whatever editing application you're using.
There's a lot more that could be done but that will get you started.