Hello fellow League of Legends players. I have been playing League since about the middle of S6 and in that time I have come to know the awesome potential that Soraka can bring to a game. Soraka is one of those champions that is very situational, however the situation, while generally uncommon is one that is quite simple to obtain. That being that Soraka is an amazing support, provided that your ADC is competent. Soraka is the ultimate **** blocker, her heals make killing your team mates a real chore for the enemy team, and late game her heals are so high that you have to make really bad mistakes to lose any team fight. While everyone knows her she is rarely played and NEVER banned, giving you one hell of an advantage when it comes to selecting your champion. All you need is a good ADC and you'll succeed in all your endeavors. With that said, lets get started!

Honestly you can take whatever Summoner Spell you want here (other than heal). Teleport would be good if you want to support your team as a whole more early game, while Exhaust will help you more in your own lane. Ignite might work if you want to confirm kills better while Barrier will give you more room for error in engages. It's really up to you, but remember, it's your choice, so ignore those that try to force what they want on you.

This is fairly simple but is the core part of this build, if you take anything away from this, this section is the most important, because while an AP Soraka does have some advantages, your healing capabilities will benefit much more with these items that boost your healing power.
Eye of the Oasis is your first item, and other than getting Boots of Speed and Catalyst of Eons you should rush this. It allows you to fulfill your warding job while giving you a nice bit of CDR and a truck load of regeneration. It also allows for a constant stream of gold to get your other items.
Next you need Boots of Mobility, as they will allow you to get places fast, without wasting your Teleport if you chose such a Summoner Spell.
After this, Ardent Censor is a must buy, as it gives you added CDR, AP and Healing boosts to buff your heals and bonus Mana Regen, ensuring that you can cast spells for as long as possible. With the addition of bonus Movement Speed making you faster so you can have more of a chance to heal your allies, this item makes you significantly stronger as a healer.
Following this Redemption is an excellent choice, as it can give a nice party wide heal, which is especially good in team fights, as well as buffing your Healing, CDR, Health and Mana Regen AND giving your extra health, again making your heals more effective.
At this point you've almost maxed out your CDR and you should really focus in making yourself more capable in the constant battle situation that occurs late in the game. Your penultimate item should be Rod of Ages. This'll allow you a bonus in Health, Mana and AP and the stacks will pack a little punch against enemy squishies that attempt to target you. But what's by far the best is the Passive; Eternity. This will allow you to gain Mana as people start to target you, so you can cast spells that will in inadvertently Heal you as well as your allies as spending Mana refunds 20% of the cost as Health. For someone that uses their own Health to Heal, this is especially useful.
Finally you will need Warmog's Armour. This'll give you a massive amount of Health Regen, as your Health will now be above 3000, as well as capping of your CDR. With all these items you'll be Healing a massive amount, and will be able to stay in combat for a very long time.

First you're going to want to build into the Inspiration Tree, starting with Kleptomancy. You're constant poke and need for pots will make this very useful in gaining gold and keeping your Health and Mana up.
Next you need Biscuit Delivery, as this will also help you early game with steady gifts of Biscuits for your Health and Mana regen.
Now it's time for Future's Market, allowing you to put all that lovely extra gold to good use by going into debt.
Cosmic Insight is going to be the rune to cap off your Primary Tree, buffing you with bonus CDR, Max CDR, Summoner Spell CDR and Item CDR. This'll allow you to heal faster and hit sooner.
For your Secondary Tree you are going to want to build into Resolve, getting Font of Life and Revitalize. Font of Life will allow for your ADC and other team mates to last longer in battle against anyone you proc this on by Healing of every hit they land. Meanwhile Revitalize will allow for you to buff your healing increasing your capacity to be useful for your team.

Soraka does quite a bit of damage to squishy people at the beginning of the game, so your Q is a vital first pick, leave healing to your second as it won't likely be any use that early anyway. With this you can be Regening your health constantly while tilting the enemy team all the while. Your E is third because at this stage it's fairly useless. Early game, its only use is zoning, while Mid to Late game it's purpose is to improve the success of ganks by rooting and silencing those aggressive mages. Make sure to increase your Ult whenever possible as it is the ultimate **** block in existence. The only thing that might be more of one is Zilean's Ult!

Early game make sure to harass the enemy with your Q as much as possible. It has a number of uses, namely giving your regen a boost. If you use it try to take advantage of the slow it incurs and root with your Q. Also if your ADC is low health Q an enemy and then W your ally. This will give them the regen boost too! Try not to waste your W on topping up health, especially early game. Only use it when the full effect of the heal would be used. This way you don't expend any unnecessary mana or health, remember that the ADC will almost always have life steal and all champions do have health regen! Your E is great for zoning and silencing so make sure to take advantage of foes with abilities that force them to stand still and shoot, like Jhin, Xerath and Caitlyn and make sure to trap enemies that come too close.

Don't. The only time you should ever touch a minion is if the tower is going down, you are the only one in lane or if you are lowering it for the ADC.

It is important to remember that a Soraka by herself is not going to be much good. By herself she is like half a champion. However put her with another champion and the combined total is more than two champions. What this means is that she can make another champion at least twice as dangerous but is no danger on her own. Bear that in mind when you play this build, Soraka is a support through and through so keep her with an ally at all times. Make sure you keep warding for the safety of your ADC and the ease of your Jungler for ganks.

So that's Soraka Support. If you take away anything this is what it should be:

She is no good by herself, so stay a team member.
She is not to be played without a good ADC, or you might as well not be there at all.
She can take any Summoner Spell you want, so ignore anyone that says otherwise.

With that said I hope you enjoy playing Soraka as much as I have and go out there and heal your team as the ultimate **** blocker on Summoners Rift!