I'd be happy to help! And I may do a more official tutorial on this since it's not explained very well, lol.
The basics...well finding a pattern is easy. I use the deviantArt stock image section, they have a huge collection of patterns. Open the pattern in whatever program you use. Hit Crtl+A to select all and Ctrl+C to copy it, and paste it into your main piece. Now, I always do the flat colors of whatever I want to have a pattern. All you have to do is link the pattern layer to the flat colors. Then the pattern will only show where the flat color was set up.
That...was a terrible description. I don't know if a visual will help but... [link]
she is so BEAUTIFUL !!!! Her hair are so cool !!! MY I WANT THE SAME !!!! I don't know why, but every time I look at her, i think of Megara...I think it's the hair, it looks like the style used for Meg Her personality is so well captured in this drawing !! She seems so nice, gentle, friendly, with a bit of shyness. She always seems lost in a daydream, like she is here but not here at the same time you know ?? I love her big dreamy eyes I can't wait to see Elly