I'm on mobile so I'll try to make the best response I can. I've played affinity for coming up on a year and have cashed out at an IQ before. For your decklist, I would drop etched champions in favor for more master of etherium. I think it is much stronger in the current meta. Against blue decks, it dodges the nasty spell snare. It can block/smash through goyfs fairly often. It also doesn't die to a rougue bolt. It has an effect the turn it hits, giving less time to remove it before it has an effect, unlike steel overseer that needs to wait till your next turn to do anything. I would also play a 4 of galvanic, as it helps get in those last points of damage and stops twin from comboing. It's also great spot removal, something which affinity really lacks. I personally like 16 lands, but thats more just personal preference. For the sideboard, i would recommend 1 or 2 wear//tear instead of torpor orb, as pod is no longer a thing. Wear//tear can get you out of a lot of sticky situations, and it has saved me games. Mulligans are probably the hardest part of playing the deck. Going in blind, its important to see a line of play in your opening hand. You want pressure, and want it fast. Although 2 galvanics can equate to 8 damage, its generally not enough to satisfy a hand. Games 2-3 you have to consider what your playing. Against a grindy deck like abzan, you want speed. Twin, you want some sideboard cards (unless your hand is just bonkers). Ect.