This is my gallio build i start by equaly lvling bulwark and righteous gust cause it allows you to push the mobs on lane real fast much like janna would, just pop bulwark the cast rigteous gust and see the minions drop like fly's, this also enables you to stand mid or take over a solo lane if needed i.e. incase u have a jungler or if there is a unfortunate double kill on one of your teams lanes.
I use Flash Clarity, Clarity because gallio is quite heavy on the mana use even if you don't lvl resolute smite till late game, Flash because it allows delivery of your ulti right into the heart of the ennemy team possible taunting all 5 with carefull delivery.
I start with doran's ring because it allow's you to stand on lane just tahat bit longer cause of the mp5 on it, it can ofc. be sold w/e you need that bit of extra cash cause of a early recall or because you are starting your 5th or 6th item and you want the space for something better.
The Item build makes gallio a all round nice tank with good armor and magic res and even a pretty descent amount of ap.
Sry for the typo's, flame all you like but this is the way i play gallio and i do very nicely with it, hope you will to!