Thank you all for all of the tips about the QUARTA QLine Metro map I was working on before! They helped me significantly! In fact, I started over to try and do a better job.
I thought I'd give a progress report on how the newer version is coming.
After looking at the Cam Booth map tutorial that Myrcia showed me, redoing the "knotpoints" or major junctions following Histor's tips, and trying the "sketch the whole system and simplify" method Isleno mentioned, I managed to come up with a rough scheme where the entire map only uses 45 and 90 degree angles. I started off planning to go for a full Viginelli-style approach, but found the lack of curves surprisingly nice for the system and design elements, with a few exceptions (there are a couple jarring corners at times).
Speaking of corners, I ran into the same struggle that I've seen Cam Booth talk about many times on his site, having some routes or parts of the map come out much more simplified than others. You'll notice that the 5 (the orange line) is pretty smooth all the way through, with only about two 45 degree angles (well, 1 visible. There will be a couple more when the map is finished but you get the point), while line 8 (the light blue line to the top right)... well...you can't see all of it here, but because of the strange routing and large amount of tight curves, it's basically a weird zigzag XD
But as a whole, I'm liking the way this version is coming out much better than the first one. I plan to add in the land masses (and maybe large parks) last, though I am vaguely planning in my head how they will work with the map.