Embrace brushes and textures and mess with grunge artwork
Adjustments are important for any kind of composition, but especially for grunge art. Grunge is meant to look messy, but sometimes adding a Photo Filter, a Vibrance layer set to +15 and a subtle Curves layer can bring cohesion to the picture.
Grunge artwork relies on a lot of blocky, sometimes low-resolution images to create its signature distressed, worn look. The Cutout filter is the perfect tool to reduce your images to just a few simple blocky shapes; background images look great with the Cutout but try duplicating your subject image and using it as an overlay. Turn the Fidelity down to 1 on the slider, move the Simplicity down to 4 and then experiment with how many Levels look good.
Wall textures make fantastic backdrops to grunge artwork, as they evoke street art. Save your wall background as a PSD file, then head to Filter>Distort>Displace, and displace your other layers over the wall layer to give the effect of your layers being pasted over the wall. Experiment with various textures to layer up in the background too, including industrial and urban images like cities. Some of these textures might look good with the Cutout filter.
When layering a grungy piece of artwork, there are hundreds of great overlays on the internet designed for adding a rusty or destroyed look to your pictures. Add them over the top of your artwork and set the blend modes to Soft Light, Overlay or Screen depending on the effect you’re looking for. Screen is good for keeping the light, scratched elements of a texture, and Lighten does the same job, but it makes affected colours blockier in the picture.
Custom brushes are the staple of grunge artwork but it’s very hard to define exactly what one looks like. Paint splatters, scratches, sprays and pencil scribbles all look great; just be as creative as you can and don’t be afraid to get messy. Work on a different layer for each stroke and switch up the blend modes to get various effects from your brushwork. Use low-opacity grunge brushes on subject layers’ masks too, to create a more weathered look.