One of the best things I learned when I was studying art was to look at my work through "new eyes." I was told that before I considered an artwork finished, or if I was having problems making decisions about what to do next, that I should hang the piece somewhere I would come upon it throughout the day.
It's one of the great things about having a design wall, but if you don't have one there are other ways to get the same result.
I recently finished piecing my Tufted Tweets quilt. I'm working on quilting the borders around each block to set the quilt for further embellishment. When I don't have it in my hands, I have it draped over a couple of chairs in my dining room.
Since I can see it from my kitchen, (where I spend way too much time), I have a lot of little opportunities for it to catch my eye. I'm still trying to decide how I'm going to embellish it so these little glimpses can sometimes give me ideas, without the pressure of having it in front of my face too much.
Sometimes once you've finished a big piecing project you're just plain tired of the quilt. The colors which used to seem so bright and cheerful now look dull and boring, the design you loved has become a chore when you remember all the trouble you had with it, frankly, sometimes you just need a break.
This is why it's a great idea to have at least two projects going all the time, particularly if they are in different stages of production. I love to have a quilt in mind, one at embellishment stage, and one pieced and ready to go. This way if I get bored with one piece I can shift to another. If you do this you will find that you'll go back to the previous quilt with a new perspective, as well as do your best work on the quilt you're currently working on.
The trick to this is to make sure that you don't wait too long before picking up the various projects, or you'll end up with an excess of WIPs, which we all have too many of already!
However, for me, the habit of using "new eyes" helps me on a regular basis. If you're stuck, try it and see if it works for you.