Hey, I've been a Miss fortune main since the end of season 4 and been playing LoL off and on since season 3.
I finished season 7 with a 60% win rate over roughly 200 games and averaged 10.1/5.9/8.9.
I would play a bunch of other champs with win rates of around 35-50% which is imo why I didn't make it into plat last season.(Might just be boosted though kappa)
Been reading a lot of MF guides on here and although most are good in detailing how to play MF, I feel like I could add more than what has been said.
First ever guide so go easy on me and I know I'm not the highest ranked player but I still feel like I know how to play MF very well, I know the format is ugly but I will make this guide a lot prettier in the upcoming weeks if it gets a good response,much love <3

Items are somewhat tricky as it depends on who you're versing in lane, the enemies team comp, who's strong and who's weak etc.
always start dorans blade, I use to start longsword in favourable match ups to snowball faster however I feel like the life steal and health you get from dorans really helps you a lot early even if it is a somewhat free lane.
most games you want to get B.F sword on your first back if possible, if not get pickaxe and long sword/boots.
B.F while maxing q will allow you to auto,q backline minions for the full q damage proc which if you got B.F first back you should be doing roughly 1/4 of the enemies hp bar(depending on adc) with this combo alone with the help of scorch, love tap, arcane comet and the extra crit damage of killing the minion.
After getting bf I like to build into duskblade buying Dirk first for the lethality.
after duskblade I finish the Infinity edge, as this is around the time team fights start happening, this adds a lot of damage to your q if you manage to get the crit as well as giving your ult a chance to crit early which is insane damage.
after Infinity edge I like to buy Rapid firecannon vs auto attack reliant champs like caitlyn so I can have extended trades without being destroyed by their dps , or If I'm versing a skill reliant champ like jhin I like to get youmuus for the extra damage as well as the youmuus passive to run down jhin as it's a pretty easy match up.
depending on which I got first, rapid firecannon/Youmuus, I'll buy the one I didn't get next, for team fights you really need the rapid firecannon to get that dps out as you can't only rely on your ultimate/burst.
next item I usually build is either Guardian angel if I'm fed and they're tunneling me, or if I'm versing champs like zed, talon or other champs that can easily burst you.(if theres no threat of dying get this item last/sell boots for it if its really late in game and death timers are very long)
if I feel like I'm doing no damage/ they're healing my damage I'll build a last whisper Item, champs like warwick diving in just healing up I'll get executioners calling to inflict grevious wounds to reduce that so he can be killed.
I sometimes get exe calling sooner than that though, mainly verses a soraka in lane, as they tend to stand way back so you can't really poke them to stop them from doing heal so I like to buy B.F>Dirk>exe calling>finish build normally.
This is because soraka can just heal the adc of the poke damage from your q making your laning phase a pain and making it a bit harder to snowball and as you're maxing q and not e you can't really poke her much from range, I sometimes do put extra points in e if the soraka is being really annoying.
Other items you can buy: Black cleaver, Although I don't build this much if they're stacking a stupid amount of armour and last whisper with your lethality items is still doing no damage this is a good item to cleave away that armour, as well as the cleave passive stacking with your ult and giving you more hp to give you more time to cleave.
however since the nerfs to black cleaver I stopped buying this item as "Core" as I believe there's better options.
Merc scimitar/edge of night are other Items you can purchase, Get one of these only when you keep getting hooked by thresh/blitz/naut or similar cc that will let the enemies kill you without you being able to flash or if you're not confident in dodging skill shots, I don't purchase scimitar often, but sometimes I get edge of night vs hook champs and activate it prior to ulting. where as scimitar you still need to be hit with the cc to activate this item so you can't use this item to cancel cc to continue your ult as your ult will instantly stop, But it can still be a game changer in some circumstances.

With boots I tend to buy them after B.f and duskblade but before completing Infinity edge.
Boots early on Mf imo are not needed as you're able to use strut to roam and can even use the movement speed boost to dodge cc like morg's binding and thresh hook.
Keep in mind getting auto attacked with remove the speed bonus from strut.
I only upgrade my boots in certain match ups/ when I really need too.
I tend to get tabis if I'm versing someone like caitlyn/Jinx and we're going even and having extended trades or if enemies mid/top/jungle are really strong and auto attack reliant.
I get merc treads if the enemy team has a bunch of slows and other cc, and if the cc is really bad build merc scimitar.
I buy swiftness boots if the enemies don't have real cc but have a lot of slows and if I'm playing on roaming a lot as it provides the highest base movement speed stats of all boots.
for the most part though I try to avoid getting tier 2 boots unless it's really needed.

Abilities really depends on your play style, I play MF in a way where I snowball my lead in lane and then roam to help team once I've made the enemy adc go really far behind.
For this reason I like to start q get a point in w then another point in q.
This allows for you to aa them applying love tap, activating w while q'ing them and following that with another aa, this should be your main way of poking as it can be done in the time that the enemy can do 1 aa as long as you start the first auto attack as they're going for the last hit on a minion.
I get make it rain as a form of cc/long range poke/ lowering the backline minions at level 4.
Since it has a high mana cost compared to other skils you should be trying to use this as your free skill with the rune manaflow band.
I then max q for harass in lane, maxing either w or e next depending on how the game is looking, for the most part though max w if you're still in lane or max E if you're team fighting for the aoe slow and damage.
putting a point in your ultimate at 6/11/16 in all games.

While team fighting you want to look to constantly throw out your q while enemies are standing behind each other, as the chances of you bouncing it from a minion in the middle of a team fight is unlikely, However you should always be looking at minions positions in team fights to try and set one up as hitting 1 double up in a team fight can be just as game changing as your ultimate as you can half hp any non tank champ for the most part.
While team fighting you should be changing targets as much as possible as long as it doesn't require you to be poorly positioned in the fight, The extra damage from love tap is really good against anyone in fights.
I'd avoid changing targets again only when it would put you in a bad spot, or when there is no way of killing the second target and swapping may lead you to not be able to kill the main target.
I personally try to save my E to stack with my ultimate as the slow it provides basically makes your ultimate do more damage as it will take enemies longer to move out of it, as well as the added aoe damage.
other times you want to use your e is when you're kiting or when you're chasing someone down.
with your w you want to try to keep it activated as much as possible for the added attack speed/movement speed, keeping in mind that getting auto attacked will disable this and that hitting a new target with love tap will reduce struts cool down.
I try to activate strut after the first auto attack as in most cases the other adc will match auto attacks with you, which would disable your strut but if you use it after the auto attack and let their attack hit first you can have it enabled for longer if they decide to run.
Other than that you should always be trying to hold your ultimate until at lease 3 people are stacked, try to get 4-5 people if possible but for the most part you should be trying to ult in every team fight and holding it for too long can result in you dying and not using it at all, or the enemies splitting up to avoid it.
so yeah aim for 3+ enemies with your ult.
You can also use this item as a way to execute enemies that are just out of range of your e however I would only be looking to do this if your team has already won the team fight without your ult and you're using this for the ace.

Miss fortune Imo is the easiest champ to last hit with because her passive love tap adds to your damage meaning that you don't have to time it as well as other champions.
If you have split minions that are going to die at roughly the same time you can start your auto animation on one of them and q the other allowing for you to get both at once.
Another way of using q to farm which I don't see other miss fortunes using as most get E first is that when you come from leashing your jungle you can use q on 2 of the frontline minions while autoing the 3 frontline, this lets you get all the cs while being able to clear the wave faster than most other adcs allowing for you to get to level 2 faster which then gives you the chance to all in at level 2 for the kill, at lower elos this can result in a kill in many games as players don't know the minions needed to level up and even if they see you get the level advantage they don't respect the extra stats you get from it.

Miss fortune has one of the best lanes of all adc's if played correctly, which can be used to snowball the game.
level 1 like I said you should be using your q to quickly kill the frontline, after that you should apply love tap to all backline minions and try to have all minions killed by the time the 2nd wave hits.
I like to hold my q when the 2nd wave comes and apply love tap to the 3 frontline minions, because of love tap you kill minions faster than most adcs allowing for you to get level 2 first.( always keep in mind it takes the whole first wave and the 3 melee minions of the 2nd wave to get level 2, you should always be aware of your enemies minions and your minions, this will allow for you to avoid getting all in'ed at level 2 while allowing you to abuse the enemy if they're not aware of this).
Before getting B.F you will need to auto backline minions twice before your q will be able to crit, you should always try to leave 1 backline minion at low hp and q it as the enemy laner walks to cs/poke or just positions poorly.
for trades in lane you should always be trying to watch your laner as they go to cs and when they do you want to poke them with your auto,q,auto combo allowing you to win trades 90% of the time, however you don't want to be taking minion agro at early levels as they can result in really bad trades if the enemy autos you also.
with your E you should be using it as poke with your manaflow band mana refund as well as using it to poke backline minions after you get your B.F.
You should always be poking with Q in lane and pay attention to arcane comets cooldown and scorch and when both are up you can E,AA,W,AA,AA and you should win most trades.
there are some match ups you want to switch up your play style but for 90% of adcs this combo should allow for you to win the trade, champions like Draven and Caitlyn however can out trade you.
Draven out trades you if he has 2 axes spinning and caitlyn can stand back and use her range as well as her other abilities to trade back.
for most lanes however you should be more worried about the support and what they're doing as they will determine if you win the trades for the most part, try to abuse supports(and adcs) cooldowns to your advantage. For example if thresh misses hook you have roughly 20seconds where he can only flay/auto attack you so you should use this time to get your poke in without the chance of being cc'd and potentially killed, while keeping in mind his flay and flay powered auto attack and his lantern shield.
If you are able to get an early kill as miss fortune the lane becomes yours.
recall and buy items and just don't let them near the minions, zone them and force them to lose cs and gold and if they don't respect your damage do a full rotation of your spells to show them that they should afk in fountain.
Miss fortune snow balls so hard in lane so if you get that early kill you should signal to your support that they should play agro if they're not already.
as you will be pushed while ahead always be careful of jungle ganks as you have no escape and try not to be too far pushed if your flash is down.
if you ever do fall behind in lane just stand back and keep trying to poke with your q, even if you're not killing the minion if you're maxing your Q it deals quite a bit of damage which can set up for ganks which can get you right back into the game.
If you fall really behind you just need to be farming and alerting your team if your laner is roaming, you can still team fight if you have B.F dirk while behind as your ultimate should still be able to out damage them even while you're behind, however you should just be trying to farm and get back to even with your laner before roaming too much.
Also if you're getting a gank you should always drop your E as that alone with the presence of your jungle can instantly force a flash and if they don't and continue to walk through it then they will be forced to flash 9/10 times.

There's a lot of text in this guide so I'll just keep this part simple.
Trading- AA,Q,AA, this should be done when enemy adc goes for CS to punish them in the time that they can't AA you.
Trading while ahead-AA,Q,W,AA,AA, if you're ahead you can still swap targets but focusing on 1 champ can be better at times.
Trading with support near without minion agro at low levels-AA,Q,AA,AA support,AA adc
Fighting in lane-E,AA,Q,W,AA,AA, swapping targets when possible
Team fights- AA,Q,E,R,W,AA,Q,AA, swapping targets when possible
When ahead half hp enemy laner pre 6- AA backline minion,Q,W,AA champ,E if going for kill/Can afford to put it on CD and lose the slow CC
When ahead half hp enemy laner Post 6-AA backline minion,Q,E,R = instant kill
FLASH COMBOS -obvious but might as well add:
flash AA,Q / Flash Q, you can't flash autos or your Q both of which apply love tap damage.
Flash, E, Ult -Can be good if enemy team are poorly positioned but keep in mind you just wasted your only escape.

Miss fortune is a great ADC to main and can easily stomp low elo, She's also a very good champ to learn ADC as a role as with love tap csing is much easier then most ADCs allowing for newer players to focus on other important points of ADC such as wave control, trading etc.
So yeah if you like the idea of being able to 1 hit the whole enemy team with your ult or just have some interest in playing her I'd say just jump in and give it a shot, shes pretty easy and once you get use to lining up her Q shes really annoying to verse.
Also you should try this play style and if it doesn't work for you check out : this guide by Jovy :[8.4] Guardian of the Sea & the Stars - MF ADC, This guide is really well formatted and well put together, And goes over some other aspects I didn't add to this guide.
Anyways if you got to the end thanks for reading <3