This is my first guide I've ever made and I've never done anything like this before, so it probably won't be perfect, but I thought I would share my current build for Neeko, how I use and combo her abilities, and how I tend to think while playing her. I am a Gwen main, so you might want to take some things I say with a grain of salt, but I found this build to be pretty strong whenever I played with it (and needed somewhere I could keep my build up on a second monitor), so I thouht this might be fun to write and share if it might be useful to anyone else.

Playing Neeko while focusing heavily on burst damage through her abilities turns her into what is one of the simplest supports in the game. The combo that you focus on with this build is just hitting your E and then using your Q on the person who was rooted by your E.

Neeko's E is a skillshot projectile that will do a decent amount of damage when it hits and root the enemy in place for a bit. It travels at a decent speed and is as wide as most champions, so it is a very easy ability to hit as well. This is a very strong ability in lane, as it not only permits you to be able to hit your own abilities on the rooted enemy easier, but can also allow your teammates to do the same.

Neeko's W is also a skillshot, but it is a bit more difficult to land. When you use it, it fires a ball upwards that then lands wherever you aimed and does damage in a small circle. If an enemy champion is in the circle, the small circle of damage will explode again, dealing even more damage. It can explode two extra times, so maximizing the amount of time enemies are within the circle to be hit by it is always going to get you the most damage out of this ability.

Neeko's ult combo is just as simple. You move into a position so as to hit as many peoople possible with your ultimate and then you use your ultimate. Quickly after your ultimate ends, you should use your E to root and enemy (or enemies if you can hit multiple) and follow up with your Q. Against many champions, this will be more than enough to kill. However, Neeko is a support, so you should almost always be near enough or fighting with at least one teammate so that they can guarantee that you get the kills. (Although I find that a Neeko with this much AP can easily kill most people you encounter 1 on 1.)

While Neeko is very strong in a 1v1 or a 2v2, she will absolutely excel in team fights. Once your teammates have engaged, you should focus on immobilizing your enemies through using your E or your Ult, so that your team can kill them. Bursting down any enemy in a teamfight, however, will always be helpful, so use all of your abilities to make sure your team wins, especially if you dont have full confidence that they will get a kill.

Another important thing to mix into your combos is Neeko's passive ability that she recieves through her W. She recieves an empowered auto attack after using two normal auto attacks that deals bonus magic damage. Because this scales with her AP, this build allows for her to deal a lot of extra damage by mixing in auto attacks with her combos.

The most difficult abilities to use out of Neeko's kit are her Innate Passive and her W, as they do not do any damage on their own and without using them properly, they wont fool anyone. Her Innate Passive allows her to turn into nearly anything on the map including your own teammates. You can always turn into your teammates, but standing next to anything else will charge up your ability to turn into that as well (Indicated by a ring that charges up around the thing you are trying to transform into). You can use this to your advantage in order to convince your enemies that you are not there before quickly using your abilities to deal suprise burst damage. While you are in lane, some of the safest things to turn into are either wards or minions. If you become a minion, join the minion wave and wait for them to come and try to clear it. When they do, punish them with a burst of damage.

Neeko's W ability is probably the most difficult to use, being that you have to go out of your way to try and trick someone. When you use her W, you send out a clone in the direction that you are aiming; This clone will also match whatever it is you have turned into with your Innate Passive with. The most effective way to use this ability is out of a bush, sending your clone out can make your enemies think you have left the bush when you haven't. You can also use this ability while you are running away, as it gives you a small window of invisibility. When you are running, you can send out your clone in the direction that you are running and quickly turn and run in a straight line in the other direction. If done right, you can even run straight through a group of enemies that believe you are the clone. Lastly, while your clone is alive, if you hold alt and click to move or recast your W ability again, it will instead move your clone, which could make your trick just that much more convincing.

I hope that anything in this guide might be able to help you, otherwise I just hope you have fun and don't tilt.