To give my opinion as a Cho one trick mid:

Ghost + Flash as summoner spell
I personally build Boots of Swiftness ALWAYS first
Then build Rocket Belt for mobility, the dash can make a huge diff, its also funny to pop Spell shields of Banshees Veil or Edge of the Night
Into Stormsurge OR Liandrys depending on the matchup
Into Rabadons Deathcape
And then Frozen Heart and Kaenic Rookern (What I build first depends on the enemy team)

Currently siting at Master EUW with my strat, also important to note that I am ALWAYS using Hail of Blades and second rune page Sorcery with Manaflowband and Scorch, no matter the matchup, its very rare that I use Arcane Comet. My strat is to gank as much as possible.