This guide applies to Adobe Photoshop 6.0 or later versions.
First, open a texture in Photoshop. Before we can modify it, some modders saved the textures in 8bit(256 colors). So, go to Image -> Mode, and change the format to RGB. The following instructions will use the first texture of 9of9's Jem'Hadar attack ship for example.
Scroll down filter menu, find texture, select "Craquelure" filter.
Still inside texture filters, select "texturizer" filter, and choose "Sand stone". This step is optional but recommend, see the pic for difference after applied this filter:
Now, open my damage template "damage512a" which is attached with this post.
The damage template is made based on the original work by Pneumonic81 and knox1711. Select all and copy. Paste it onto your texture.
Save your texture as new file, don't forget to append a D after the original file name! e.g. hull.bmp -> hullD.bmp. The final effect in the game: