Honestly I don't feel like telling you what to do since everyone has their own play styles. I only created this so that you can see my build. It does tons of dmg XD.

Anyways like any other ap mid champs try to farm and play safe till you reach level 6. Try to get your enemy to half hp before you hit 6. Once your level 6 you can for sure finish them off. One thing about Orianna is that most players don't know.... is that you use your ultimiate first before you press your w. Your ultimate radius is a lot larger and it collects enemies in 1 spot. What's the point of hitting 1 enemy with your w and then hitting everyone with your r. wouldn't you rather hit everyone with your ultimate and then hitting everyone with your w. BTW DO NOT GET ATHENES UNHOLY GRAIL FCK THAT SHYT ORIANNA PLAYERS WHO GETS IT ARE FCKING ******ED YOU DO NO DMG UNLESS YOU ARE FCKING FED!!!!

My orianna build does not have any defense other than the liandrys. I used to get rod of ages on her but It doesn't do as much dmg. Your goal as orianna can to be either to poke with q and w then go away or go ape shyt on squishys. by the time you get void staff your q w combo can at least take off half hp of squishys. NEVER GO FULL ON IN THE MIDDLE OF A FIGHT! make sure you stay all the way in the back! you are squishier than adcs since you don't have armor runes nor hp.