Hi i am making this build for Diana so you can get a easier game to play. This is my main build for Diana (haven´t tryed another) so hope you like the build and now i will tell a little more about it.
for Quintessence i take Greater Quintessence of Potency. i take this runes for early game AP
for seals i take Greater Seal of Potency i use this for some early game abilite power
for marks i take Greater Mark of Insight and i use this for magic penetration early and late
for glyphs i take Greater Glyph of Celerity i tkae this runes becuas i need cdr on my ultimate so i can use it more often if i dont wan´t to use my ``Q´´ abilite first
my masteries is a little random but i have tryed to do my best so i have playced my points on ap tree and a little tankynes magic resist and armor becaus if they gank me and it is a ad jungler i will get the defens from armor and magic resist for my opponent
i start with boots of speed and three healt potions becaus that make me easier to run from ganks and dodge abilites. Then i buy two Dorans rings for the HP and AP so i can get a little tanky from that in early game. Then i buy death fire grasp for doing some dmg on the tanks. After that i buy catalysate the protector for hp and hp and mana regen when i level up then i go for rod of aghes. And now am i tanky enough to go in and fight them in a 2v1 situation and survive and maybe kill someone. Then my rabandons death cap comes in so i can do some dmg and win team fights for the team. and then i go for a quick abyssal scepter then boots (it is my opinion that i you should buy boots in late game but you can buy them earlier if you want to). and after that i buy my last item to maximum my dmg lich bane.
I am speking on my ``Q´´ abilite first becaus it is doing the moost dmg from the first abilites you get and then i try to max it as fast as i can then spek on ulti in level 6,11,16 the other abilites can you look at in my guid.
i am using the classic speels flash and ignite becaus i am comfortable with this speels but if you want to you can use flash exhaust or ignite exhaust.
this build is for mid laner and you will get around 3k HP late game. and i am sorry for my bad english hope you will enjoy this guide thank you.