Well the community has given me alot so i thought i'de give somthing back in the form of a tutorial about weathering. I prefer heavly weathered Tanks, tanks that look as though they have been used constantly and neglected, after all IG wouldn't really take alot of care of there tanks, because they have so many

Step 1 Base colour
FIrst up, the best method is getting a good constant colour, like it's brand new off the factory line. Tamiya spray paints are cheap and provide a good flat colour, but the best option by far is the airbrush. I've good the cheapest of them all but does the job. I stopped Drybrushing years ago because it's simply not the look i'm after, and personnaly, the technique sucks. So a good flat colour is the starting point.
Shown here on my bassy.

Step 2 Weathering
Here is where the fun begins, Colour fades as time goes on. Normally I use some filters for this, but thats quite advances and all cover that in a later tutorial. For fading and rust I use Tamiya's makeup or weathering masters.

These sets are by far the best thing, and i stress everone must get one. They are $12 Australia, thats somthing like 7 euros and 4pounds. You just water it down and place it on, instant rust, and instant fading. I use the rust first and then apply the soot next.