In short, you look at the big picture, and your sideboard is as important to the big picture as your main deck is
Instead of it being restricted to just the owner, though, it goes into effect for every player in the game, giving your opponents a shot at gaining land
Considering his second ability makes all your creatures unable to be blocked, any cards that grant you monarch become potentially game-enders when you have a big board
Green makes huge creatures, blue is defensive or evasive, white gives creatures counters, and black and red focus on power first
If you fix your mana early, Temur Battlecrier will pay you off
You can open fracture foil Japan Showcase cards, mana foils, and extended-art cards in Foundations Collector Boosters