You will need to remove 18 card to get to 60: - 2 Mystic Forge and 4 Deadly Dispute - Affinity is an aggro deck; it wants to put additional creatures on board, not just draw cards. You may leave Thoughtcast and Thought Monitor. That will also rid you of black color entirely. - 4 Mistvault Bridge - 22 lands is too much for a 60 card deck that mostly plays free spells. You also don't want to draw multiple tapped lands. - 2 Shrapnel Blast - You don't want multiples in your opening hand, because then you won't have enough artifacts to cast your spells. You are also playing another sacrifice outlet (Arcbound Ravager) and too many sacrifice effect have diminishing returns. - 2 Myr Enforcer - You were playing 12 7 mana spells, that's simply too much. You can't keep opening hand with 4 of them. - 4 Lotus Petal - The only card in your deck that was not Modern legal. Also it's useless in longer game.

After these cuts, your deck has 60 card. However, 10 of them are non-artifacts, which may be more than you would like.

I will also give you a few other tips: - If you are too low on 0 mana cost cards, try Memnite or Welding Jar. Jar does something even in longer game, unlike your original Lotus Petal. - Nettlecyst - Acts similarly to the Cranial Plating, but comes with a body and has a good toughness. If you would play it, I suggest that you replace them for Arcbound Ravager, as they are doing opposite things.

1. Considering that you play Ball Lightning, you should play a mana-base that is almost exclusively red. I suggest that you play 1 Swamp for situations when your opponent plays Path to Exile. Rest of the lands should be dual lands - Sulfurous Springs, Blackcleave Cliffs, Blightstep Pathway  ^Flip, Foreboding Ruins, Reflecting Pool.
2. Thud could be replaced with Callous Sell-Sword. The disadvantage of Sell-Sword is that since it targets the creature, it can be killed in the response. Other than that, it's an advantage.
3. Consider playing Witch's Mark instead of Thrill of Possibility. It's better against counter-spells, and if there is no benefit to play it as an instant, the Wicked role is a clear upside.

1. If you plan to play Rune Snag, then it's better to play Consider rather than Opt. It's actually relevant that you can put cards into the graveyard.
2. Into the Roil is obsolete. Replace it with basically anything else.
3. In pauper, Faeries with enters-the-battlefield effects are usually combined with few ninjas. Maybe add two Ninja of the Deep Hours