credits to @Nyrolol and @khatarinaeuw


Early: Most of the time i would go Flash + Ignite with the AP Build. Start Doran's Blade or Long Sword most of the time and if you are aggressive laner.

Your Primary goal is to reach lvl 2 or 3 so farm and soak XP. At lvl 2 and lvl 3 you can look for trades, that favour you, time enemies CD and go all in when the enemy has no CD since Conq gives you a huge advantage! Since you have very bad early game and your kill isn't guaranteed, just going even in CS is a huge advantage. Look to have a good reset with cannon wave, most of the time you can roam directly after it. Either your Opponent pushes you into tower, so ask your Jungler for help, or you can actually push the waves fast and look for roams, especially if you go Sorcerer's Shoes first back, or just build Nashor's Tooth Components and farm that item. Never look for 1v1's if you don't understand your dmg but rather 2v2 and 3v3 Skirmishes.

Midgame: After your first Item, you can actually fight people, but still your primary goal is to roam or fight 2v2/3v3. Teamfights are your strongest point, especially with resets, so look to kill the squishy backline. Try to setup your daggers, either Q'ing Minions or W and run away. You rely on hitting your Daggers and full channel Death Lotus, so try to avoid CC at all cost, play it patiently and wait for your team to engage first. (Do not engage first that's a huge mistake most of the time)

Lategame: Lategame Katarina is very glass cannon, you either 1 Shot someone or get 1 Shot, so play very patiently & wait for someone to engage. If you get rolling you can clean up fights very easily.