You might not agree with me, but in fan missions, for both Thief series and Darkmod, level design is often the weakest part. We mostly want to tell a story, build cool or "realistic" locations, and we think about populating these locations as we go. Not that I'm a good level designer, but all these years I've been collecting tutorials, books, and GDC PowerPoint presentations about level design, and I want to share a few of those with you. I paid for the books, so that would be illegal to share,