Lug practice: Fitting the "top tube" to the lug.
Today I learned: Raw tubes and lugs never fit well. Never sand/file the tube, only the lug. Use a half-round file to open up the lug socket so it's a loose fit over the tube. Since there's no good way to clamp a lug, this is a painful, file-into-the-skin-on-your-fingers process. Lugs suck. However, they do make a good template to scribe around for the tube's miter. Did I mention I cut myself, and my hands are really sore/tired now? Yep.