1 - take teemo top or mid (preferrably top)
2 - take sorcery + precision and ultimate hat
3 - if you win top lane then go mid after you take tower and put all mushrooms in middle lane, try to put as much as possible. if you lose top lane, go mid before enemy take your tower and again put as many shrooms as possible and try bully enemy mid laner a bit.
4 - all game long you must put mushrooms in middle lane and you must get 40% cdr asap.
6 - all the time you must make yourself annoying to the enemy team so they come to mid lane to kill you and then they walk all shrooms and your team kill them easy
i have 9 wins and 0 loses with this strategy in rankeds now silver 1 after promotion games