Quote Originally Posted by Asharad View Post
I have one more thing you should know. If you make a mistake, and want to erase part of your pattern, don't use the eraser tool. Instead change your brush color to black, and start brushing out the parts you don't want. This keeps your pattern from being destroyed, in case you decide to brush it back in later!
I agree. using layer masks in GIMP/PS is an incredible non destructive technique. As Asharad mentioned, using the eraser on you main layer will permanently destroy your pattern, while painting black/white onto the layer mask will modify what shows through and can be changed at any time.