Seth Godin has written a nice piece about Critical Path. If you are an engineer or project maanger you will likely have dealt with these terms quite a bit. When I was working on my Izannah pattern, my husband consulted with me so I could set up a "What needs to be done when" path to getting the pattern done and printed and out there.
For artists, sometimes WE can be the block in the Critical Path. It's good to identify what the blocks are. For me, with folk art doll making, it is making limbs and dresses. I sure love to sculpt! LOVE to sculpt. I do not enjoy making arms and legs. I have creations that have hung around for years waiting for arms and legs. So now I know that I must make arms and limbs BEFORE I even attempt to make a torso.
Knowing what to do is important, and figuring out the best order to do them in for you is equally important.