graphicxtras.com > How to combine multiple swatches / fills / patterns in Illustrator CC CS6 CS5 etc tutorial
Tutorial by: Andrew Buckle
Works with: Illustrator
Platform: PC / MAC OS X
Other tutorials: Tutorial links
Videos: Video tutorials
AI format files. They (on this site, anyway) are all seamless tiles. They come in a variety of colors and artworks - see more via the swatches page but how to combine them, how to blend them into something even more super colorful and amazing for use in your projects.
Key panels via the window menu, appearance and graphic styles
You can go to the right side menu and clear appearance to get to a decent start point. Go to the swatches panel and select an item (can be any of the ones on the site or any other sets). once you have one applied fill then go to the add new fill or duplicate command (same menu as before) and add a swatch. You will only see that one now as the lower down fill is hidden by the top artwork. Go to the opacity section (it is displayed as a link next to the fill in the appearance panel) on the latest fill and set the opacity to say, 50%. Or set the blending mode to darken or lighten etc and depending on the fills, more or less of the underlying fill will be seen.
Some of the tiles in the various sets do not need to use the opacity / blending mode. Some of the tiles already have that inbuilt and can be combined multiple times without the need to change the opacity etc. You can also shift the artwork in the swatch (or scale or rotate) via the object menu transform (the key thing is to set the transform object option to OFF and put the pattern to ON)
Once you have added all the fills and strokes then you can go to the graphic style's panel and select the right side menu and select the new style option and save all the combinations into the style's panel