I have previously (November 19, 2013) posted about negative space in portraits. While negative space adds interest to most portraits, it is even more important when adding texture. Here are the before and after versions of a portrait of Karen Hernandez:
In this case, two textures were added to the wall, but only one of the two was added to the concrete balustrade and balusters.
Here is another example of texturizing negative space, this time featuring Tina Tiara:
Again, even more interest and mystery has been added by the use of textures. As in the previous example, the wall behind Tina has two textures added, and the wall on the right has only one of them applied. Negative space behind the model can take more texturizing, whereas negative space in the foreground should have less. Otherwise, a strong foreground texture may draw the viewer's eyes away from the model.
Finally, here is an example of Andrelica:
Here, the roman shades provide negative space that could be used for adding textures. This image could also be cropped any number of ways:
However, if the uncropped version is texturized, this is the result:
In summary, textures need their own space in the image. Images with negative space are ideal for adding textures.