Hi, I'm a Rakan main, I got an S+ my first game and continue to get a- or higher most of the time.
This build is about poking enemies low, making plays and most importantly, keeping your adc alive.

P.S. Ignore some grammar, punctuation and spelling mistakes I'm just a tad lazy since I just updated this from 8.13 to 9.23 (current Oceania patch)

I enjoy Rakan due to his ability to dance around the battlefield, weaving in and out of combat, keeping friends alive and his enemies in the air.

I personally like to play Rakan very offensively, going in with a w, auto, q, auto, then ulting them both (you can ult then w instead of just w-ing). (this combo has great poke, can give you an easy kill on bad players and is great for keeping them away from cs. Also Rakan is very good to tank abilities/auto-attacks due to his passive. As Rakan you tend to be the initiator for your team and will begin most teamfights (late game try to target your q's healing for a low friendly. I also have high standards as a sup in general and will never ks unless it is unavoidable (someone else can't get it), nor will I have over 20 cs a game although this has changed due to relic shield.

Rakan's R is game changing and will not only decide team fights but win you lanes, and games. His ult can easily net you kills when coupled with flash and w. I during a team fight will use a combination of flashing on or closer to enemies, w onto enemies or through them and using e to dash through and charm enemies.

When you are with the rebel, Xayah, you become even more overpowered due to the e range buff and her w can help proc the keystone you have at that time, as well as the general synergy (having a friend who's a Xayah main definitely helps ;).

I personally enjoy Prototype: Omnistone as it can let you do a whole range of things. This rune also replaced kelp sadly. If you enjoy roaming might be best to replace magical footwear with stopwatch, cosmic insight can also be traded for approach velocity if you have azreal ashe or a team with good slows.

For Secondary Runes I normally take resolve (you can take sorcery sometimes too tho,) and I take either Demolish or Font of Life but Shield Bash will also work well with passive, Try to take demolish if your able to push alot against your matchup. Then you can take overgrowth, bone plating, revitalise or conditioning. This comes down to personal preference.

Spellthiefs and Relic shield are interchangeable depending wether you will be poking more or playing more defensively and need more sustain.

Knight's vow is pretty essential since it just has good synergy on rakan, normally use on adc.

Ardent Censer is pretty good on rakan as well and can help alot since he has 3 defensive utility spells being his q and both e's as it will buff adc's attack speed and the overall power of shields and heals.

Randuin's Omen can be good against high attack speed high crit adc's such as draven or caitlyn, can also help against yas.

Locket of the Iron Solari can be pretty useful especially in team fights and has that extra little bit of magic resist and ability power.

Zeke's Convergence is a good item on rakan since his ult has such a strong impact on the game.

Banshee's Veil can help if they have too much cc and ap. also gives solid ap to you.

Athene's Unholy Grail can work well with Ardent Censer and will help give your team just an extra bit of sustain. I mostly build as a last or second last item.

Shurelya's Reverie can give good ap and can help land r on their team due to the extra speed. Can also assist in disengaging.

Gargoyle Stoneplate is a solid item for some more resisitances and tankiness.

Mikael's Crucible can stop the enemy's cc and like Ardent Censer increases heal and shield power.

I start with w so I have cc and a way to get my adc out of situations, then follow with e so I can w, auto then e away for small poke then q so I have even more poke (and because its the last ability left lol). afterwards i get w and e level 2 so my poke is up and then I continue based on what I need more damage and cc, w, more shield, e.)

Pros:
Great poke
Great survivability (for you and adc)
Great sustain
Double Shield
Great cc
Amazing speed
Amazing initiations
Cons:
Bad turret pushng (ever since they nerfed Xayah's W)v
Small Healing without AP (Shurelya's)

Flash is generally good and what i normally take.
Heal is pretty nice and can give speed boost as well as some clutch health and is generally what I also take.
Ignite can be good, I generally won't take so I don't ks (Rakan also has ALOT of damage early anyway).
Teleport is what I'll take if I have a Xayah adc and a hard machup or sometimes if my adc also chooses it but there is normally better spells for the situation.
Exhaust Is a good spell when vs-ing someone such as Draven or Xayah or who both have very high early game dam.

Rakan is a great poker, and has amazing survivability (including keeping his teammates alive).

So play offensively with most matchups, own the stage and don't let someone else take it from you, dance in and out of the battle field, keep your team alive and their's dead or air-born.

If this guide helped or didn't please vote, let me know whats wrong and i'll work towards improving it.