Mate
Welcome to Armorama. We are a hive of information. Try searching through the various forums and features. There is a ton of info in there - not necessarily in the aircraft sections but still applicable - which can be a great help.
What scale is this Spit?
The decals have gone on well - no sign of silvering.
Some people suggest washes of black/burnt umber to bring out the panel lines. I haven't mastered that yet so I use a .3mm propelling pencil - lightly sand the lead on one side to give a slight edge and then use the panels lines as a guide - if you overshoot then a gentle rub with an eraser removes the error.
I can't tell from the photo where the dark earth is in the upper cammo. Something i have only recently discovered, and tried, is using a slightly lighter mix of the original colour gently sprayed into the centre of the panels to give them a slightly faded look.
Maybe a few scratches in the paint work around the wing walk and engine panels - these can be done with a silver artists pencil or with silver paint and a thin brush/toothpick.
That's just a couple of ideas - other may have a few more.
Again - welcome to the friendliest site on the net.
Brian