(this is my first guide so there might be things missing and things i did wrong and it is super short)because of leblanc's design to get in and out of any situation, I normally would win using her,the only times i lose is when i get trolled(normally not a problem unless multiple trollers) or someone rage quit on my team, for some reason people always say leblanc can only silence for 4 seconds, but this build allows 6 seconds of silence then two seconds 0f rooting and 2 second silence again with full build(can use full combo every 14 seconds,3quarter of the combo every 7 seconds), and no blue required in any part of the game and enough mana to use for a long time

leblanc is an assassin focused on using combos and bursting people down, she's mostly famous for the ability to mimic her spells and can cause the longest continuous silence,rooting and able to teleport to and back, if played correctly she can teleport 5 time in 15 seconds ,note: if ability continuously used asap after cool down of the first 15 seconds,LB can only teleport 3 times every 15 seconds until w and r are both refreshed (note: the third teleport is by it self, the first and second one is in a row and the forth and fifth is in a row.E.G 1st&2nd teleport 6 second cd 3rd teleport 6 cd 4th&5th teleport

at lv 1 use w to keep enemy away from creeps waves(unless enemy is able to fight back heavily )
at lv 2 use q,w,w combo to keep poking enemy until lv6
at lv 6 normally most champions would be dropped below 40% health or had to return to base by this time,lv 6 is when leblanc's deadliness nearly doubles, if the enemy managed to stay in lane then kill them with a q,r,w,e combo or if requiring to take them by suprise use, w,q,r,e combo
with full build q,r,w(when the first silence ended),q(when the second silence ended,e,

talon: most talon are very easy to fight against early game
lee sin(mid lee sins are very rare): stay behind minions to be shielded from most of his abilities if he tries to even get close to the creep waves use q,r,w,e combo (usually enough to take out 30% of his health)
ap yi:(this one needs some skill)stay behind castor minions to be untouchable by his alpha strike, use combo to fight back when alpha strike ends
lux: no need for explanation use w,q,r,e to fight her when she casts skills
teemo: since he's a hit and run champ in early game,simply spam skills at him until he dies,
twisted fate: most tf's need time to get their w set up to fight back so take him by suprise and stop him casting with silence

leblac's not good with area damage,but she take out single champions one at a time(try to sneak in to the team fight unnoticed)and should only attack adc and support to get out faster(best to just attack one if the enemies are op and you need the escape skill) , lb attracts a lot of unwanted attention.

pros cons
harasses hard need lots of gear to keep being op
easy to run away tiny amount of health makes her weak in team fights
can 1v1 champions(unless fed) very vulnerable to champions with stun,root or supress

the best fighting location for leblanc is where there is complicated terrain,using w then r makes it easy to chase people and easy to run away.