i try to keep philosophers Stone and heart of gold for as long as i can to milk out as much as i can, if you play smart support and stay back you can get the upgrades for them before you get your boots because you shouldnt need to run away from a fight if you keep your lanemate full. Aility power only ups 1ap - .25 healing so i dont find it as important early on if you get that cooldown and mana regen you can just keep healing over and over. i go with the archangle staff because it ups both mana and ap so you can heal more often as well as more amount. Also if on my first trip back i will pick up another 4 mana pots because I focus on g/s early and delaying my item completion, you dont get much mana regen.

sona lanes best with an range AD champ but u can lane with any dps, you can lane with anyone who knows their champ well, you cant give out mana like soraka so it is not as good to lane with an ap cuz they will run out af mana a lot and leave you to defend but if you play smart sona is very hard to kill. Mid to Late game just stay in the middle of the pack and spam your auras you will up all defence, attack, and movement speed and with your CD items you can keep all buffs going at once. Keep an eye on enemy champs poking at group cuz if you can get Crescendo off and stunn them should be an easy kill (assist for you) i usually walk away from a win with 20+assists and even 5-10 kills (Very easy to accedental KS with HYMN OF VALOR)

CV is good since your looking out for everyone already you might as well spy on guys and I think someone should always have it on your team. Flash is a personal pref, it saves you in a lot of situations but you can replace it with anything you would like .

I find the gold/s is helpful for getting your item build early, you wont be doing much dmg with her so Creep Score will be low and getting gold will be helped more in the items, runes, and masteries. The armour runes will keep you alive early game and help make you more tanky late game. NOTE: I have yet to go play ranked so the gold runes my be switched out for a magic resistance to add do your tankyness, i find there is usually more ad than ap so i ignore.

For this build i dont recommend either of these i let my lane mate do all the killing while i keep him/her alive so leave it to the champs who do not hit like a wet sock.

Healing is priority, now I play unranked randoms so i like to do a little more dmg with my spells while stacking my passive, serious support may want movement speed maxed before damage to boost escapes, pushing, and ganks.