Is there an easy way to add moss etc, or would I need to do it pixel by pixel using the pencil? I don't have photoshop, and the only way I'd get it would be a cracker free version:/
There are free painting tools too ... GIMP is often mentioned, but simple things like Paint.Net might do the job as well. I'm sure once you ask you get at least a dozen of suggestions.
If I work on graphics I usually choose one of three methods:
- Pixel it.
- Take a photo of something that looks similar and modify that.
- Model it in 3D, render and postprocess.
Usually this way I get acceptable graphics quality. Beyond the actual painting skills your understanding for lighting, color and blending, and surface structures will make the difference between dull and cool graphics.
Warning - I was a technician most of my life, and struggled long to at least achieve mediocre painting skills. So real artists might be able to give you better advice.
Your bricks need less straight edges, try adding a small crack or hole here and there. Damaged corners. Try different shades of gray, bricks are not 100% identically colored.
Try some variation for the mortar color. if you assume yellow light, give the dar areas a bit of a bluesh stain if they are clean, or brown if they are supposed to be dirty.
Moss was already mentioned, it really likes to gro in such gaps. Stains from water might be good too, if you can do larger overlays.
Try bricks of different sizes. A pattern of two sizes might look fine.
You can check my isometric floors, ther are two tiled variants that might give ideas for bricks:
But now a real artist must jump in and help