Katarina isn't hard to learn but she is hard to master. Katarina has great damage and can get a high killing streak with her passive. You can play her aggresive or defensive, but once she is fed she is a killing machine!

The best way to use her skills or bring the enemy low on health is like this;
first hit your enemy with , then jump to your enemy with , clear it up with sinister steel and run away (now is her movement speed increased and you take less damage). When you are going to finish the enemy and not going to run, !pass the enemy! and than use .

Something about , I think this is a important item because it makes Katarina hard to kill and the enemy gets slowed when you use or other abilities. It gives you a few more hits and it may be enough to kill an enemy! I think you should get enchantment alacrity because if the enemy runs you have more chance to hit him/her again with shunpo

Farming is really easy with Katarina, just trow to the minions and clear it up with sinister steel!

Katarina is a perfect team work champion. It's great for the team to have a Katarina, she does a lot of damage in teamfights. I'm going to tell the best way to do the most damage without getting stun or being focused by the team! The most important thing is to keep distance, don't go in as first! When the team starts to fight you don't enter the fight as fast if you can but first use bouncing blades , then shunpo the CARRY! Clear the up with sinister steelsinister steel and immediately use . When they are not all dead but you already have a kill/assist is the best way to kill them after the fight to shunpo to the enemy and use sinister steelsinister steel again. Most of the times it does enough damage because they are already really low on health and you get the kills. Keep doing this (possible with Katarina's passive) and you get them all!