My own rule? Finish one project before starting another, but I will have two going at one time. Currently, I'm pretty much sticking to that rule. I have a TATW that I corrected a mistake in that is waiting for the LA that I can us to become available. (If I can figure out how to sandwich it myself, I may just go ahead and do it on my machine, not sure yet.) I also just finished the last block for a D9P, next step there is to starch the block (from what I read, this is a good way to ensure more accurate cuts?) cutting them apart, and then rearranging them, labeling the rows, and putting them back together.
I want to finish the scrapbook I'm currently working on, and I may go ahead and pull out the wall hanging that I got to go in our family room. Since we bought a new entertainment center, we had to take down some pictures, and I'm not inclined to put them back up, thus freeing room for some wall hangings instead.