Hi Everyone I'm PrinceOfNights an EUW player if you want to add me I'm Silver V Name (Kuorosaki) I did another guide for Gnar if you are interested to see there is the link http://www.mobafire.com/league-of-legends/build/the-place-of-gnar-is-at-the-top-416362
SO!Leblanc is awesome with her spells she easily can go in a fight and run easily with her W and R Leblanc has a nice damage and she is one of the best Roams Champion that I have ever played so I love to say that if you main you will get out of Low Elo Fast but don't except a lot from her in High Elo

I Love going full AP because if you kill them fast they won't get a chance to kill someone of your team so a lot of AP , a lot of kills , a lot of wins So My advice wait level 6 and get Death cap first and feed on them

Pros
First she is one of the best Mid for a lot of seasons but she got nerfed patch ago but still she is OP if you main her
Great escape (W) and you can use it in Entering a Team Fight although I recommend it but if you want to use it to chase as you want I'm not going to tell you how to play you know what you are doing.
Her (Q) make any spell increase damage she do on the same target in 3.5 secs.
Her (E) is useful for binding an enemy to get a kill or slowing them to Run
Her Counter isn't a lot.
Weak Early but Strong Late and solo Q need a late game champions I think
You can do with her a lot of jukes

Cons
She get banned in Solo Q I'm saying as for me.
If she is stunned it will be hard to Run.
You will be focused by the enemy team.
If she didn't get her target from the first time she will have to wait for her CDR.

My Advice for items is that you go Full AP so you get your target from the first time and try to not die and If you main it and you don't die a lot with her buy Mejai's Soulstealer and stack it so you get a lot of AP but If you want to switch Mejai's Soulstealer to Luden's Echo isn't bad either because you will get a lot of AP in both ways

Farming I think best way to farm is to use you (W) but watch out for your mana or just go farm with your Auto Attack like any other champion

Well I recommend going in with (W) so you do AOE damage but as you want and try to join after the tank go and focus The carrys Like The ADC so do what you want but that is my advice.

Well That The end I hope you like my guide and If you want to see my Gnar Guide There is the Link http://www.mobafire.com/league-of-legends/build/the-place-of-gnar-is-at-the-top-416362 And If you want to add me in EUW server I will be happy to play with a lot of people and please comment and tell me which champion you want do you want me to do a guide for him ^^

Love All

With Love,
ThePrinceOfNights(Kuorosaki)