Nice pics, though some might not approve of the spoiler/airbrake combo while landing (worse on take-off, though) in the first..... me, I definately approve...live life on the edge,....
(...of your 'computer seat'

)
Looks like you've got a good rig, so...
Turn up all settings (autogen, lighting, clouds etc) to max, Anti aliasing in your video card and not in the sim...AA crucial in fact, nothing ruins a pic more than jaggies
Avoid lens flare most of the time....
Download or buy ai traffic
Download or buy a weather and environment program
Download or buy mesh, landclass, ground textures, scenery
Experiment with different weather, times of day, angles...
Use F1 view (freeware) or a payware program to help take screenshots..
Look out for new stuff to show 'the crowd' to give the set 'extra value', or a theme etc for more interest
For the best tips, just look around the screenshot forums for ideas

I hope this helps...? :)
Hope to see more from you...
Cheers
Krigl