Heavy game strategy thread

In light of the recent "We have 3M subscribers but no in-depth posts on specific games" thread, I thought it would be nice to collect some strategy tips from folks here on "heavy" games. This has happened a few times in the past on this sub, and it's great to see how different people approach games! My favorite thing in board gaming is playing a game multiple times to really become an expert-- I really love playing a good game 10+ times versus playing 10 good games a single time. For me, the most fun thing in gaming is the feeling you get from learning some new strategy or idea.Suggested prerequisites for posting: 1) You've played the game ~10 times, not solo. This is just to try and keep people from posting "this strategy is busted" after playing only once, that's it.2) The BGG weight is at least 3. This is to filter out tips on Red Dragon Inn or Ticket to Ride or Secret Hitler or whatever. Sorry!3) If you've won/placed well in a tournament for that game, brag about it! If not, that's okay-- just want people to get a thread to boast :)Just to kickstart (no pun intended): games I'm interested in hearing strategy tips on include Great Western Trail, Tzolk'in, Gaia Project, Terra Mystica, Russian Railroads, 1889, Ora et Labora, Agricola, Barrage, Arkwright, 1817, Food Chain Magnate, Clans of Caledonia, Through the Ages, Power Grid, Age of Steam/Steam, Twilight Struggle, Castles of Burgundy. That's just an example list, not inclusive at all (I don't play Scythe much, but I bet people have tons of opinions on it). Admittedly I didn't check each of those is a 3 weight, but I'm reasonably confident except for Castles.