I tried my hand at making homemade seitan the other night, and it was pretty good - my only complaint was that it wasn't as firm as I would have liked it to be.  These are the steps I followed (based on "Basic Seitan Recipie" instructions on the back of a vital wheat gluten box)   Mixed vital wheat gluten with water, kneaded for 5 minutes until it was elastic. Formed into 2.5" log, let sit for 5 minutes. Cut log into 0.5" pieces. Heated vegetable broth over medium flame, added seitan pieces. Brought broth to a boil. Reduced flame, let seitan simmer for 1 hour, stirring occasionally.   So what could I do to improve this, and get firmer seitan pieces as a result? Less water in initial dough? Cut smaller pieces before boiling/simmering? Longer simmering time? Different type of vegetable broth? 
i've only made seitan myself a couple times, and it's been awhile, but isn't there a point where you drain it and/or squeeze out some moisture? if so, maybe an extended sit in some sort of press would help. the times i've made it, i put it in a smoker afterwards, so it was firm because of the low-heat semi-cooking, i guess. 