It's been a loong time coming, but somewhere in the middle of a 16 hour session last night, I finally started to get meds, and perhaps higher-level play in general
Before, whether due to not enough map knowledge or my own mental habit of trying to find patterns in everything - probably both - I was never able to allow myself the flexibility to play meds to their potential. For each med, I'd either treat it like a (lightly armored) TD, or a heavy tank. Naturally, neither quite worked. However, I've been playing a lot of T-34-85 recently, and perhaps due to it being a bit more forgiving, have started to learn the balance playing meds requires.
In reality, however, I think the changes are twofold. Yes, I'm learning when to expose myself, advance or retreat as a med, but I'm also getting more flexible in general: watching for opportunities, being willing to fall back even if I want to just take "one more shot", etc. This heightened awareness/flexibility is paying off, and fast: I had my fair share of derps as usual last night, but my average WN8 jump three hundred points over 100 games (i.e. 5% of my total games in WoT, decent sample size) - from an average of 1k, to 1300+. For most of the night it was actually hovering closer to 1500, but I kept playing when I should have stopped, unfortunately.
Still plenty of ground to cover, but considering that my minimum mental "that game was acceptable" standard has gone from 1250 to 1900 in the space of one session, I'm pretty happy with my progress this month.
tl;dr Better map awareness + better tactical mechanics + forcing myself to play smart => Profit (Higher WN8 and personal standards)