Once you have things under control and a fair amount of land in play, you can deploy your big threats
For example, the mana curve of a midrange deck might look like this: There are no strict rules to building a mana curve, and every deck has a different one
Chandra, the Firebrand Copying instants and sorceries is a neat ability, but Chandra, the Firebrand either requires a ton of mana to cast it and a spell worth copying or the luck to see it survive a turn cycle
As long as you've maxed out your domain count, Leyline Binding is a quick, low-cost enchantment that keeps an opponents hard-hitting permanents at bay, as long as you can keep it in play
Brass Infiniscope and Elementalist's Palette are archetypal mana rocks, while Owlin Spiralmancer and Unbound Flourishing help you to double up on your expensive X-costs
Me: Still too subtle but less so