for me, this is the most basic and easy type of battle damage to do. as you know most gundams who enter battle collide into other objects, leaving small dents and scratches. to imitate this battle damage would make your gundam look more realistic. this is very simple to do so don't worry about the difficulty.

materials:

>metal file [thats too easy]

so wear are you supposed to apply the armor damage? this is mostly found on the edges of it's exposed parts, or the ones most likely to get worn down.

so using the file, carefully scratch the edges using the flat or the side of the file. try putting pressure on the file making different depths of the scratches.

try experimenting with the different angles of your file to make creative results.

once you have done most of the sides it should kinda look like...

 this!

the worn out edges would look a lot better once dry brushed.

part after dry brushing and adding black paint chips.

thanks for reading!