Amateurish textures have two problems:
they aren't "Seamless"
They pulse or spot or whatever.
Photoshop has an offset command that puts image edges together. It is then possible to clone over edges to make the appearance of a seamless image. A craft.
Pulsing is harder to fix.
- an element of the texture map is distinct - knock it back - easy to do.
-the light on the image was uneven so the cross fade of color shows the tile. - very hard to balance this type of image. The pulsing comes from variations in background color.
A solution to this cross fade problem is complex but do-able:
Instead of considering the image as the texture, consider the image merely as a bump map or pattern guide. Get rid of the bad color.
•De-saturate
•make new layer behind
•increase contrast and lighten image to show more white background
•knock out the white to reveal back ground layer
•add color to background layer.
On a brick wall, this would give the impression of a painted wall. If you want to draw in the mortar joints as a contrasting color, it helps...
Another solution is to artificially build complexity into the texture.
Lay out a number of texture repetitions [already made seamless] in one Photoshop file. Mix and match parts until the assembly itself is unique.
This is equal to making a bigger texture so repeating is less noticed.
A rule of texture thumbing is that the more natural variation in a surface material the larger [more area] a sampled texture map must gather.
For example, I was once sent a small sample of a boulder wall - irregular boulders, blobby mortar. Probably done by this guy:
http://www.rense.com/ufo6/manson.htm
It was impossible to make a seamless perfect image map.
What we should have done is taken a perfect photo of a large stone wall and made a high res texture of that.
I am just beginning to address textures in my "The Artlantis Attitude" project. Even many of the commercial Artlantis textures/Shaders show this tiling problem, so a fellow needs to be good with the image editor - an essential skill.
Dwight Atkinson