With this build you will be squishy in the beginning, so stay out of line from the enemy champions, unless you have a clean shot with Hymn of Valor or your Power Chord (use this for harassment). Also try to get last hits on minions with your Hymn of Valor.
Mid game you want to protect as many towers you can alone to LvL and earn money faster (but watch out for ganks).
Late game you want to be in as many team fights as possible to earn money faster, but you dont want to be targeted by the enemy (so keep a distance).
When you have bought Rabadon's Deathcap and have 478 in money, sell Kage's Lucky Pick to buy Blasting Wand and later Void Staff.

Tip! If you are planning to hit an enemy champion with Power Chord, make sure Hymn of valor is the attack you used last. If so, your Power Chord will deal twice the damage.
But take note that Power Chord has different effects depending of what ability you last used

Summoner Spells

The reason i have Flash as a spell is to get out of tricky situations, it can be from a gank or to avoid getting to mutch damage from towers.

I use Clairvoyance to try finding the enemy's team positions.
When the game starts i wait for ten seconds and then cast Clairvoiance in the enemy's base (marked with a circle on the map depending on what color your team is). This allows me to know what items the enemy is buying and get a good guess were the enemy champions are heading.
I chose a lane and walk to the tower and wait until my Clairvoiance spell is ready to be cast again, i then cast it in the bush on the side of the lane (marked with a cirkel on the map depending on what color your team is).
This is to see if any enemy champions is hiding in there.
If im going mid lane (NOTE! i only go mid lane in mid game or late game with other champions from my team) I like to cast Clairvoiance in the bushes marked with red cirkels, also this to look for enemy champions.

Runes

The runes i have chosen is

• Greater Mark of Magic Penetration

• Greater Glyph of Scaling Ability Power

• Greater Seal of Scaling Mana Regeneration

• Greater Quintessence of Health

Greater Mark of Insight will increase your magic penetration. this will aid you to harass early in the game, and be to some help later in team battles when you attack with Hymn of Valor.

Greater Glyph of Force will also help through the game, you will get an early bost of ability power to aid in your healing with Aria of Perseverance and attacking with Hymn of Valor.

Greater Seal of Clarity is just there to make sure that you have enough mana to cast your abilities (the regenerating effect will increase per LvL)

Greater Quintessence of Fortitude. Except from Giant's Belt and Rylai's Crystal Scepter, this quintessence is the only helt increase you get.

Skill Sequence

The skill I have chosen is to start with is Hymn of Valor, this is to be able to keep the enemy champions away from minion battles and to earn experience points.
After that i chose Aria of Perseverance, this to be able to do some support healing at all in the beginning.
Third i chose Hymn of Valor for more power to that attack.
Fourth i chose Aria of Perseverance, this to be able to heal better.
At LvL five i chose Song of Celerity, this to get the extra speed it gives and to actually get a point at that at all, cause as you can see i have chosen to max that ability last.
LvL six, I chose Crescendo. I don't think i need to explain this.
At LvL seven i chose Aria of Perseveranceagain, this for the fact that you are a support and need to be able to heal your teammates.
After that i alternate between Hymn of Valor and Aria of Perseverance until LvL eleven, then it's time to put another point at your ulti.
At LvL twelve another point to Aria of Perseverance,
and LvL thirteen a point to Hymn of Valor
At LvL fourteen I start to give points to Song of Celerity again, and another point to it at LvL fifteen.
LvL sixteen is it time time to level your ulti again.
The remaining points is used to level Song of Celerity

Items

In this guide i have chosen to give you the ful list of items to buy, but I will only explain the more advanced items.

Chalice of Harmony is an item who I think is necessary for sona due to the fact that she uses a lot of mana. with Chalice of Harmony she will able to use her mana to the fulles, and have a fast regeneration when she needs it.

Tear of the Goddess. Yet again she uses a lot of mana, and this item will make sure that she keeps here mana from draining.

Kage's Lucky Pick will give you a money boost to get the more advanced items.

Ionian Boots of Lucidity, mainly for the cooldown reduction it gives, it will allow you to keep all three of your passive auras that Sonas abilities is giving out to your allies at the same time.

Rylai's Crystal Scepter, mainly for the ability power and health, but also due to the fact that it slows an enemy if its hit with an spell attack.

Rabadon's Deathcap. If you have come this far in the game that you can afford this item, you will be overpowered. It will give all your abilities an enormous boost, due to the fact that it increases your ability power enormously.

Void Staff. this is just an extra item that will give you further power and make you more overpowered (that's if the games go on for that long)

Farming

If you want fast money, make sure you use Hymn of Valor as often you can to last hit minions.
If an friendly champion wants help with getting a natural buff, you can assist him and kill the creeps that are around the mob with the buff.
In team fights you should use your Hymn of Valor to try and kill some enemy champions, this will give you an advantage in money making

Pros / Cons

Pros:

With this build you will get a lot of ability power, this will fawor your healing and attack with Hymn of Valor.

Due to the fact that you have much ability power you will be able to fight in team battles.


Cons:

As Said you will be squishy (but this shouldnt be a problem as long you have a good distance betwen you and your enemy).

You must depend on your Hymn of Valor to last hit minions for the money (so you can afford all the items).

Match History

I will upload more history the more i play as Sona

In this match i managed to get eight kills with Sona, this due to the fact that i got last hits on enemy champions with Hymn of Valor and Power Chord (you might call this kill stealing, but it's necessary to get the money).
I also died seven times, that was because i didnt pay attention to situations when i was vulnerabel to ganks.
you may also see that I am missing an Kage's Lucky Pick. This is because as soon i sold it to buy an Blasting Wand, the enemy team surrendered.