A gessoed, heavy brushstroke surface works well. See the blog post "Creating a Texture to Scan." The texture should be optimized to tile (covered in the previous blog post), and the resolution should be 200 to 300 ppi.
I started with a fully rendered painting, then made a composite Layer from all of the visible Layers (cmd-opt-shift-E).
|The beginning illustration. Click on any image to enlarge.|
|Composite Layer (cmd-opt-shift-E).|
To create a “bump map” texture over a selected area (or over the whole Layer if you don’t have anything selected), go to Filters > Filter Gallery > Texture > Texturizer. Next to the Texture drop-down menu there’s an icon for a flyout menu that allows you to load your own texture.
|Use the drop-down menu to find your texture. Photoshop also has presets.|
Click on the flyout menu and choose your texture to load. Adjust Scaling and Relief.
Consider blending the texture effect by lowering the Opacity for that Layer.
|Use a Layer Mask to tone down the texture in some places.|
One problem with this method is that the brushstrokes are more or less random and don't follow the form. You can remedy this by using the Bristle Brush (on a copy composite Layer, of course). I prefer the Round Fan Stiff Thin Bristle variant, but I like to lower the Bristle Count to around 40% (on the Brush Panel). You can paint across the form to give the object dimension.