Just keep repeating one of the sections and see if you can extract a second from it. Or maybe a third of a second from each. That's about the difference between nailing a high-speed turn and not quite getting it right, so concentrate on those.
I.e. Schwedenkreuz (actually, the entirety of the first section), Fuchsröhre, Klostertal, Tiergarten, etc. - also, Karussel to Schwalbenschwanz is another area that time can be lost, at different points from lap to lap. Get it right consistently and you could easily find a second overall. 👍
In fact, the track is so comparatively vast, and thus so hard to learn, that a tenth of a second on ten corners is almost guaranteed to be "available", but that's harder to keep track of and evaluate.