I find that SS + locket + chalice keeps you in the game perpetually, while literally spamming your abilities. I believe your mp5 is most important. Not AP, not damage, not survivability (arguable actually). If you can stick around spamming your abilities on GCD then your team will be fiendish. With randuin's omen on top of that you can get down to 4.4s CDs.

CD runes are ftw but currently I use my Shen page (MR, HP, HP/L)

I just tried her.. and yeah she is crazy squishy. I love playing support like Janna and Soraka.. But Sona is so different from my first play. At least Janna can shield herself and run with movement speed and soraka can silence and heal herself with a defense boost. It seems like when I tried to run with defense up and speed boost, it didn't matter much to their shaco. It just seems like all the bonus her auras gave, were too negligible to really make a difference. And if your stunned, you're done. I can't really say that's the same for Janna or Soraka cause they can avoid it or counter it (janna can shield, soraka can silence).
So I'm looking forward to trying these ideas out to see if maybe I can last more than two hits. The ultimate is the one that seems like... useless. The stun never really seemed to go off, I saw them dance, then immediately pummel me. I didn't even see much dmg done. Also I thought the passive only effected her ap, not her physical attack as well? So how do you really time that then... Can you turn off auto attacking?
She seems really fun, and I'm sure I can learn her... But that first game was a total wipe.

Janna is definately more difficult to kill, between her shield, tornado knockup, snare and aoe knockback for sure. Soraka's much worse off than Sona, because at least Sona can move around fast. I build Sona for tanky aura benefits because it makes you able to get in there and do your job without getting swatted like a fly (see also - AP Soraka trying to get in range for Starcall spam), and with Randuin's slow effect + Celerity, you can usually get away unless their whole team is chain snaring/disabling you.

Sona's ultimate is her main teamfight ability. Wait 'till a lot of people are lined up for it before using it. Alternatively, if you have an initiator such as Amumu or Malphite, time Crescendo to go off right as the effects of your initiator expire. It's only a short stun, but if you aim it well it is a recipe for sucess. You can also save it for when that Twitch or <insert dangerous channeller> shows up and begins doing their thing. Whatever you do, don't just fire it off because you can hit one champ with it, you need to try and decide when the right time to cast it is. Usually, that is when both teams are committed, so you can give your team an extra second of dps time. Or of course, to help ward off a gank/suceed in a gank of your own.

Her passive adds to her auto attacks. Cast 3 spells, and your next autoattack will do a decent chunk of bonus magical damage. Ideally in a teamfight you will rotate all 3 auras, and have a second of free time before the first one is ready to cast again. In that second, you autoattack a target and use Power Chord on them. It won't be amazing damage come late game, but even then it's going to do 200 or more damage to their squishy, so it's not negligible even if it isn't consistent dps.

To get the most out of Sona, you need to be moving around a lot to ensure your team is always benefitting from your auras, without being so close to the enemy team that you become a prime target. Make no mistake about it - you're probably top of the kill on sight list for the other team, because when you're around, they cannot catch anybody to kill them. Even if you do get decently tanky, you're not going to last if they start pounding you for being too far forward.

I just want everyone to know that I find AP Galio to be a GREAT laning partner. You both have long range harass making them killable behind turrets. Their ults in conjunction nearly always land a kill.

I also like laning with Yi and babysitting him late game. He should be fed or atleast well off since you laned with him and pushed / killed. Late game you can follow him around shooting auras, heals, damage, and movement buffs from behind trees. But you can really do that with anybody. It just seems that with Sona you can overcome Yi's biggest weakness (disables)

I played Sona yesterday, at least 15 matches, only lost one and that's because 2 players DC'ed. From my experience, you don't need too much MP5, Just MP5 Runes, and Innervating Locket. You will be good on mana for the entire game. I finished a lot of games just with a locket and Mercury treads because they would end too fast. Your goal as Sona is to keep a distance from the fights, just stay behind your teammates, and keep them up, just rack up those assists, I've had games like 1-0-22, 2-0-19 etc, I don't die very often with her. Enemies always chase you. I find cleanse to be effective and flash, example, Amumu pops his ultimate on you (it happens), no problem, Cleanse, flash into the enemies around him pop your ultimate and let the teammates do the work while you get back. Just because she can heal herself does not mean she can survive all the time, the speed boost is great, but players can still chase you down.

I don't have a main build, it varies. But I usually get MT Boots, Innervating Locket, Ralais Scepter early on if I need the extra health, if I'm doing well, I'll get mejais first then go for my deathfire Grasp then Glacial Shroud if the AP I currently have heals enough to win every battle. I only play arranged games, I'm pretty sure my build would be different in a solo match, but my teammates pretty much build characters consisting of Tanks and High DPS. Very organized in keeping me alive. I have not played a solo match with her which is probably why my matches are so successful and haven't even had to do a complete build yet.

But from experience just get innervating locket and cool down reduction items. If you're keeping your teammates up, get some armor+CDR items like Frozen Heart. Your goal is to stay alive and keep your teammates up, nothing else.

what are peoples' thoughts on an early Chalice instead of the Locket? i know it doesn't fit your "aura-*****" theme, and you trade off extra healing for magic resist. but strictly from the standpoint of longevity in-lane, keeping your mana up. typically, i start with a Meki's Pendant, and if things don't go terribly, i can usually build Chalice + level 1 boots by the time i ever go back to base (more often than not, with a decent lane partner, i can stay in lane upwards of level 10 or so before going back to buy). i try to build Tear asap thereafter. i find once i have my Chalice and Tear, my mana problems are virtually over, and i can then commence to roaming the map helping gank/push/participating in team fights.

but i see most people touting Locket highly. i haven't tried it yet. idk if it's just because of the Champion Spotlight, or if it is truly a superior item.
thoughts?
again, this is strictly from an early-to-mid game mana regen/staying power standpoint.

Updated the guide after having played a game with her post-nerf.

I don't think she's changed too much except her early game, where the mana nerfs are very noticeable and very painful.

Changed the item build a bit (nixing the catalyst for a chalice, which is very much necessary now imo), also changed the rune recommendation a little.

And no, I still won't recommend a Locket unless you're running without runes or masteries. Locket is not necessary. Stop leaning on the item as a crutch, people! Spending that much gold on an item for mana regen purposes when you could have gotten a chalice for less than half the price is foolish!

Minor update to keep the guide up to date with the present nerfs.

She still plays exactly the same way as before, only her W is now so mana inefficient, that you lose lane control if you take enough harrass that you're forced to spam heal.

Sona players should be passive-aggressive now. Settle for slapping them with a Q whenever they get into range, without going out of your way to chase them down to do it (unless it's safe to do so). You can't afford to be spam healing when you're paying so much for so little.

And yes, this means she is hard countered by any champ that can harrass decently. Not that she wasn't already, but it's more pronounced now.

Updated for the current patch, since there is no more Locket I no longer need to keep the small section about it in the guide.

Item build has changed again, with the Shurelya's buff and Randuin's nerf. Been having a great amount of success with this current item build.

Long-due overhaul, bringing the guide up to date with the latest patch. Made some changes once again to the item build, primarily in making the core item build smaller to facilitate proper warding. Numerous edits that only serve to make the guide wordier.

Still taking any constructive feedback.

The new passive is absolutely incredible, by the way.