When I was being Katarina I Figured out that Amplifying Tome help's you Reach Katarina's full potential because I get 23 AP and 59 Damage at Start of the game!! when I did my best game my Score was 36-3-16 but i was going top at the time but you Still can get good Score's going mid you can also see how to play midding Katarina as you can see below the Farming Chapter. my build is all about Stacking AP Mejai's Soulstealer help's the Stack's for good game Start's. also Hextech Revolver is a good Source of AP and Spell Vamp that's why I get it in most Round's.

As you play Katarina you will need more Money late game! So what I would do is Farm alot When your team doesn't need you, but if your team has a Jungler do not Jungle. Dragon is one the Buff's that takes lvl 18 Katharina but with life Steal you can take it! Down! Follow my Build to get the best kills in a round. farming is not only a good Source of money but also XP but Katarina is not a Jungler she still can Farming!

as you may not Know that Katarina can also be a midder my Build can still can get you good kills in a Round I got 17-11-15 Score in that game. so Follow the build and you can also be one of the best Katarina ever (Besides me!)