Thank goodness I found, and joined, an online dollhouse building community! The members there recommend doing a "dry fit" of all the parts in each stage of the building process before you do any gluing. Good thing I listened. These houses don't exactly snap together. Tabs have to be whittled down and lined up perfectly for everything to fit.
There were several times during the dry fit that I was very, very, glad that I was only using tape to hold things together. Some of the pieces had to be reversed, and others arranged differently than I had expected.
Everything is quite square right now, but that's because all the pieces are fitted together. When I'm doing the actual gluing I'll have to do it one piece at a time and if I don't get each join perfectly square it could mean the pieces that come later won't fit together.
This is a LOT harder than I thought it would be!
Oh.....and in case you haven't noticed? Petunia is trying to get your attention. . . . . . .
She's modelling her brand new, hand knit, cashmere dress.