Not Updated For Current Season
The First ability to get is distortion, mainly because it will help save u from early game gank, and that Sigil of Silence is not as good until u can use its secondary function of silencing the enemy. don't go for early game gank with Leblanc. wait till level 2 so u can silence them. and always level up Sigil of Silence when u can(except for the ult.) for entering combat wait until u can cast Sigil of Silence on them then cast your ult as Sigil of Silence. The next attack you should use, is distortion to activate the secondary of Sigil of Silence ult. once u get Ethereal Chains you can engage them first with normal Ethereal Chains then use in order Sigil of Silence, Sigil of Silence ult, followed by Distortion.
Use Teleport to stay in the lane as long as possible early game and to support other lanes that are getting pushed hard. Flash is your get out of jail card. when your spell combo does not work or you can't get away with only Distortion, distortion ult then u can use flash for a 3rd wall jump or to get away( distortion will get u over walls just remember that it's short range will mean you have to get close to a wall before you can jump it). Flash can also be used to tower dive an enemy with low Hp. u can use it to get out or in, depending on how you use Distortion.
The First items on the list are Doran's Ring And Health Potion. I get These for survivability plus the AP for better early game. try to stay in long enough so that you can get Amplifying tome and Sorcerer's shoes in one go, but if you can stay in longer do it until you can get Majai's and Sorcerer's shoes, but don't stay any longer. next get Tear of the Goddess as soon as you can so that you will get the mana boost faster. If you can stay alive in team fights or in a lane still wait till you can get Archangel's staff in one go. other wise if you are getting hard pressed to service go back and get blasting wand first. after archangel's staff get another Blasting wand to go into Rylai's Crystal Scepter. while most players will get Giants belt first you should not this time. being able to stay ahead of the enemy on ganks or team fights is the priority. for get it second or all in one go if you can. the next item is Needlessly large Rod. this is for Zhonya's Ring which you should Get all in one go after Needlessly Large Rod. if the game should for some strange reason last long enough for you to get a last item. I get Void staff for the only reason for more AP and That your enemy's are sure to have gotten magic resist by now. so it will help you kill them no mater what items they got.
'Note - This Setup is for people who have fast reaction time so that you can unload all of your spells at a moments notice.'