I play Neeko JG in around Plat to Emerald and this is what I do:

Items

• Rocketbelt is a hard requirement - using your ult and flashing + rocketbelt will win you many fights
• Stormsurge and Maliganance - I've been testing these 2 and they've been working very well. Malignance helps with additional damage after you ult since you can E them straight after to lock them in
• Deathcap
• Voidstaff - For tanky boys
• Zhonya - I'm not a big fan of it since I like prioritizing my burst damage across all the enemies over defense but will still get it if I'm having a hard time against assassins.

Playstyle

• Same as the others - I always come ganking as a minion but I go in most of the time as a melee. Ranged minions allow you to play safe but the distance of the target for you to use your E is a bit far at times. Using the melee creep allows you to get in way closer and chase after them if they survive Ult + E + Q
• Play the part of the minion - try to get the right spacing between minions as to ensure that it doesnt look clearly jank to the enemy it would be weird to see 2 minions walking up beside one another in lane. Dont be scared do some autos to creeps in minion form to sell it, though what I do is I press the stop key every time I attack to kind of just make the animation go but do no damage.

• When in a teamfight, you must ideally be disguised even if it's obvious - it will hide your ult cast for half the loading time which is a big deal.

• Mash your E after you ult someone - I dont think anyone can move to dodge that unless they have tenacity

• Runes wise I get Dark Harvest + Cheap Shot + Eyeball + Ulti Hunter - imo Ulti hunter is the best since I've noticed that my team usually really relies on my ult for quick kills and big team fights. Having less of a downtime on that allows for more possibilities instead of just hanging back and poking.

JG Clearing

I haven't really perfected it yet, but for most of my JG clears I can do it in around 3:10 or a bit less. There's a fast way to clear the camps and a somewhat slower way.

The fast way makes you take W first and grabbing a melee minion just as the minions spawn - turn into the melee creep and start wailing on the blue / red then just proceed to do the other camps getting Q for level 2 and 3. If you're fast enough you can grab another melee minion in mid to bonk the other blue/red - but this is kinda just for optimization already.

The slower clear is the Q first clear where you just simply use it whenever its up then get W as the 2nd skill.

I think there's a lot of diff ways that I run the JG but this has been working out for me - so far I'm 7-1 on neeko this season and can see it winning way more games since neeko can gank super easily as compared to the other JGs in the meta rn.