Not Updated For Current Season
The masteries shown here are not yet updated for the current season, the guide author needs to set up the new masteries. As such, they will be different than the masteries you see in-game.
Dorans ring:u need it very much cause it gives you just the right amout of mreg as you need for start and HP.
2x Executionere's calling:life steal and crits very useful for surviving and endless lanning.
Boots of swiftness:well GP dosent need any other boots+with phantom very nice speed.
Guardian angel:for survival in team fights cause if u do well early game they will focus you very much in mid game.
Infinity edge:more crit damage+more crits+damage=MEGA NUKE.
Phantom dancer:too max out for 100% crits you can kill allmost anyone with that kind of damage.
More description will be added post comments about if the build helped you or too give advice how to improve it gl and hf :)