The way of applying patterns depends on what you are trying to depict - embroidery (e.g. velvet corsets) or a painted pattern (e.g.painted silk etc)
If it is embroidery, I personally like to do it like this:
I sketch the pattern with 100% opacity on a separate layer. Then I usually copy paste the small design around to form a bigger pattern (that's for the lazy ones like me:P). Then, if:
a) pattern is darker than textile: I use the multiply layer mode and set its opacity to ~30-40%.
b) pattern is lighter: I use the soft light layer mode and set its opacity to ~20% (unless it is thick, then it's best to use multiply on ~15%, as the embroidery would drop some shadow)
Then, I run over the design with a 1 or 2px ~60% opaque Hard Round brush (PS) / Ink tool (Painter) making tiny zigzag patterns (just as if you were embroidering) like a mad, mad monkey. The smaller the gaps between separate lines, the thicker the embroidery will look.
Now, when doing the painted pattern, things are a bit more tricky. Firstly, on a separate layer I sketch in a pattern and place it around on top of the textile. Then I switch the layer mode to something that grants me colorful results (usually one of the Burns, Dodges or Overlay) and slightly desaturate it, so the result looks natural.
Then it's the boring work: I run over the "blended" pattern with the original colours, adding highlights on convex areas and shadows on the concave (or what's the word) areas.The highlight and shadow hues I pick from applying the general textile highlights/shadows on top of the basic pattern colours.
It's absolutely dull to be honest, but no "automatic" blender will grant you as attractive results :/
Oh, and when painting lace patterns, my favourite layer mode is Soft Light (for white and other light colours). All you need to do then is paint in some tiny highlights here and there to make the design a bit more bold. A cool trick also is to duplicate the Soft Light pattern layer, lower it's opacity and flip horizontally.
Well, I hope it helped =)