Predecessor Builds > Countess > Mid-Lane Burst
Try to E, then Q-auto-RB-auto and then Q out if you can't kill them. If the hero you are attacking has strong escape options, try to hold Q instead of opening with it if you can get into range. This build has zero sustain until you can build passive stacks and get Lifebinder up and running. Once you have both, you can often attack your way out of a tight spot through the amount of life steal you have.
Once you have level 6, really try to bully your lane. You want to fast clear your lane after level 8+ so you can rotate to the side lanes to get more kills. Play a "dive and dip" playstyle. You want to poke while posturing for fights until you think the enemy is low enough to burst.
Your first couple levels will be very weak, so don't try to fight. Just poke to give yourself space, and try to dodge abilities. You will lose more health than your opponent, but just focusing on farming. Your health potion heals more based on level, so try to save its uses until you get a few level-ups. Once you have your first item and your ult, you can start looking for more serious fights.
Although this build has a lot of shred, countess's kit focuses on diving the backline. In team fights, focus on squishy range, mage, and support characters in that order. You can fight tanks and bruisers, but they have enough sustain usually to make it a fair fight. Against bruisers, use you Q to misdirect their direction away from you and then Q back to avoid them. You're an assassin, so if your initial burst doesn't get them low just run away and wait for your cooldowns to reset.
Switch tainted scepter for megacosm as you see fit. Feel free to change build ordering depending on what you need, but this build order gives you the best early game kill potential to start stacking your passive.
