Keeping a diary
I'm a new quilter and have used a diary to keep track of the process: each sewing session, how many blocks I did, when the top was finished, when the quilting was done, how many yards of fabric used, etc. I also have a section called "What I've learned" where I list things I learned how to do and mistakes I made and how to avoid them.
I leave the first page of the composition book blank and use it as a 'table of contents', because I also keep track of tips I've read here, neat websites, charts for figuring out yardage for borders and backings.
It's a bit messy because I also have sketches of possible settings and diagrams of blocks, but it's a lot of fun to browse through it and see my progress. And keeping track of blocks as I finish them keeps me motivated because that allows me to see progress even at the beginning.