You need hard removal to beat Elesh Norn, you also need some gas in hand to replay after and you need to not die to the +2/+2 swing from the other side of the table should that be on the cards
Once in play, however, you can simply go about playing the game as normal, saving your flicker spells to protect your commander and occasionally flickering other Scarecrows to clear problematic threats
White isn't particularly known for its ramping ability
Audacious SwapAudacious Swap is a more expensive, worse Chaos WarpChaos Warp that you can do twice if you sacrifice a creature, but does say "cast" instead of "put onto the battlefield", and therefore allows you to try and get a couple bites at the apple
Edric, Spymaster of Trest Our top Simic Elf is this powerhouse that can be your Commander
You usually get 9 out of a standard 8.5x11 sheet of letter paper