Teemo First Blood Kill: Hunting Down the Enemy Jungler

At the beginning of the game, quickly let Teemo hide on the bush and use his passive Camuoflage skill at the other team's jungling range. Let the enemy champion attack the monster and wait until his health is significantly low. Then surprise him with your basic attack with an upgraded third skill, Toxic Shot. This tactic is very effective especially when you use Ignite as well. One thing to remember though, do not let the enemy finish off the big monster before making a preemptive attack to prevent him from leeching health on it.