This may help because I run into similar time-to-time.

Right now, I'm rebuilding my data warehouse from the ground up. I've identified a number of weak areas and I'm going to improve them with some new designs and new theory that I've been wanting to implement for some time.

Some things that have helped me is plenty of whiteboard space. I normally go to a quiet room and just brainstorm ideas on whiteboards such as data models, data flows, doodles of my co-workers, you name it. I just write ideas to axe the ones I hate and keep the ones I want.

From there, I used to document and plan a bit. I would create diagrams, visio work flows and other things even suggested in the Data Warehousing Toolkit by Ralph Kimball.

But unfortunately, all the strategic planning, documenting and so forth drown me out a lot. I found myself doing more planning than actually working.

So, what has helped me the most is just winning small battles. I start working on the fragments of the bigger picture. I get something at least completed, and it motivates and provides clarity for the next fragment. Eventually, I end up with a big piece of the pie completed and I feel a lot better about the progress.

This isn't for everyone, but I found that just doing something, even if you scrap it helps a lot. This is similar to writers who may not know where to begin. Just start writing, anything, everything and maybe something will catch fire.