Salutations! Thanks for stopping by, this is my first time ever really making a guide like this; but a friend talked me into it a while back. Thanks to CannedKiller for, even though it was small, encouraging me to make this guide to the best of my ability.

Anyways, my name is WickedPoppet (You can call me Joe if you wanna add me). I've played fiddlesticks off and on when I first got into league, as when I was new back in season 4 I wasn't good at jungling; but he was my first pentakill then and I always loved scarecrows and the theme of fear. At current I am gold, and have close to 200 games of fiddlesticks this season with a 58% ish winrate. I'm at 170K, and mostly play him jungle or support; though I do go mid with him on occasion.

-He has some of the healthiest clears in the game from my experience in jungle.
-He has stellar sustain, and can have fantastic vision control (The difference between a good fiddlesticks and a bad one can be seen in how well they control vision.)
-One of the most influencial level 6 ganks of most champions, with extremely high damage potential.
-A scarecrow, like seriously how much cooler could you go with that. Oh, and he has a Pennywise skin so like clearly great.

-Very easily invaded early and killed if not smart. If you get invaded by heavy cc junglers or olaf you are probably just dead unless you get help.
-Extremely vision reliant. Due to the fact you only get effigies and control wards, you might not be able to get great vision everywhere if your team falls behind on that and the enemies wise up and ward/clear wards.
-Very susceptible to cc. If the enemies are smart, they will save all cc for you once you dive.
-He has a pennywise reference. Some people don't like clowns ;-;

Harmless Scarecrow
So, this replaces your trinket. I personally find its a fair mix of yellow trinket and red trinket (level 6 onward.) You can have a max of four effigies out on the map at once, and when they are discovered by an enemy they will do any random action (flashing, ulting, auto attacking, walking, ect.) and then perish after they finish the action or take any damage. Once you are level 6, they will reveal wards when placed in the area directly around them for 6 seconds.
Additionally, if you stand still for two seconds you will replicate an effigy. In the sense that, you will have the idle animations of the effigy and your health bar will be hidden. Also recently riot added a buff, where if you can proc your passive from effigy if undamaged. For the most part, this is a skill that can play mind games if you are willing to take that upon yourself to figure it out.

Terrify
A point and click fear that scales from 1 second to 2 seconds and does 6 - 12% current hp damage to the target. This damage is doubled against anyone recently terrified by fiddlesticks.
The passive portion of this ability, is that your other abilities can terrify champions, minions, and monsters if fiddlesticks if undamaged and unseen or in effigy. This is your "legendary 5 man terrify omg". Honestly, the best portion of this for me is that you get to terrify on your ultimate or reap, then do 24% current hp damage on point and click at max rank and basically delete almost any squishy with a full combo in under the 2 seconds they are terrified if done right.

Bounifult Harvest
This is your bread and butter non ultimate ability. This is where most of your actual damage and sustain comes from when you aren't ulting. If you manage to finish the channel or all draining targets leave the tether, 60% of the cooldown is refunded. If you are cc'd or cancel it it goes back on full cooldown.
Fun notes, these are a tether. Meaning it will continue to drain when a champion is "untargetable" so long as they are in the range. Examples; Master Yi alpha strike, Kayn ult, vladimir pool, fizz e, and other things except for zhonyas. While you are still tethering to people in zhonya's, you will not damage them or heal yourself.

Reap
Honestly the worst part about his kit right now. Most of the only things its good for is the silence, as the damage and scaling on it are negligible. Things I use it for; silence, the slow, and snatching that dark harvest proc that is a little out of reach. However, I will not when you are full build and closer to max level with some ranks in it it can fully chunk squishies. Yet again, all of fiddlesticks chunks squishies.

Crowstorm
Ah, yes crowstorm. This is your strongest ability on your kit, and lets you make powerful ganks once your 6; and potentially turn any team fight to your favor, or just dive two or three squishies mid game and kill most of all them. A fun tip here, if you ult at max range, onto a wall you can extend the range of your ult. I'll put up a few example pictures at some point.
For the most part, early game you look to simply gank everytime your ult is up. If you do, you can either secure summoners or kills. Always try to ult over a wall or from bush; never let them see you ult any point in the game if you can help it. Just gurantees you get your ult off.
Mid game you will be looking to position yourself around the map sort of like an assassin would, looking for strong flanks onto squishies assuming you aren't behind. If you are behind, try to look for points where your team will get engaged on and be ready to ult from there.
Late game is where things just get crazy. You can basically just go around with your team and assassinate any squishies faster than they can flash. And still be full health. Its at this point where you should be trying to roam between jungle paths around your team, constantly looking for good ults to kill the backliners. Then after that just help clean up.

For the most part, your pre 6 combo will be q < e < w. However, try to make sure that you silence them right as your fear wears off, to maximize how long they are not allowed to flash. However if you need to catch them, e < q < w. Once your 6, these combos mostly stay the same, but hold off on using w until you have made sure you have followed them running well enough to ensure you will get the most of the w off.