Katarina

Whatever you do, don't first pick her. It is incredibly easy to counterpick a Kat, to such an extent that she basically becomes useless.

Spam q for poke, farm, and wait for them to use their abilities to trade. Same thing for your ultimate, don't just go in at the beginning, go in after CC, abilities were used.

Im a Kat main, it mostly depends on your rank. in bronze and silver not much out play you need to worry about but gold-plat (where i am) you have to worry about being camped A LOT and being cc chained i recomend not using her if they have 3 or more champions that have hard cc such as stuns, silences, roots, and cripples

My only tip is don't use E to cs and NEVER go in if they have their CC avalaible. Lol hope this useless tip helps

Start with your Q, and only put one point on your E until later in the game. You should use your E more as an escape option than as an engage. If you have to, place a ward in the middle of the lane near your tower so you can E away from jungler ganks.

Don't rush in for the kill too quickly unless they get close to your tower - which is likely since you will probably have to do a bit of turret-minding up until 6 anyway. (Don't be afraid to stand under your tower in the early game if you have to.) Katarina is generally not good at wave pushing until you have your boots and one of your ad/ap items. Unless you're facing an Akali, which Kata can usually stomp all over.

I'm a very conservative player, though. I like to play things chill for the first 6 levels. I rarely go in for the kill until I get my R. Once you kill them or at least give them enough hurt to make them respect you, you will be able to push a lot easier. Generally I win lanes this way. Once you get the momentum in your favor and make sure you have a ward in the lane to shunpo to, you'll be practically untouchable.

However, if you're playing against a Zed, Yasuo, or Fizz, your laning phase will probably be an absolute nightmare. Be prepared to roam and divert their focus from your lane. It's really hard to win mid lane against those champs unless your jungler is good at ganking.

Vs Zed you really have to dodge the Q,s and CS when it's on CD. Try to keep up Q poke on him as offer as possible. He's squishy like you. Don't go in pre6 and don't stay in lane under half hp.

Rush zhonyas or ludens. Depending on their skill vs yours. (Ex they land most abilities and punish you often, go zhonyas. But if you can avoid most of his free damage go zhonyas and hit him with the empowered Q and chunk him every few seconds.)

Her laning is pretty weak, although if they make a mistake like using their CC on you, you can easily punish him. Mostly during laning just stay decently safe and try to have a ward to Shunpo to in case you need to escape. You should be roaming a lot when you can since most Kata's bring boots and get an early luden's so you'll have plenty of MS to out roam your laner.

Q poke/farm. Rush Zhonyas/ludens/abysmal depending on matchup. (AD Assasin/general/AP Mids) and roam. LOTS.

Look at my match history build something like that. Copy my katarina masteries

Learn EQW And EQW combo (They are almost as important as QEW)

Play with Normal cast its actually the fastest (I can explain this if you want ). Well quickcast without indicators is faster but not ideal for her

Rest is about speed. Rember you can always go faster. only limit is your reflex