I play a fair bit of support because i prefer to to fill roles that are open.

I like nami because she can create a zone in front of her ADC with ebb and flow harass so that they can concentrate on farming and not suffer being poked or traded upon but still close enough to join in.

Pros

+ Creates a nice enviroment for your carry to farm.

+ Outdoes most standard pokes in the game.

+ Because she is tanky she can get more out of her kit by getting amongst the action and buffing and debuffing the most important players

Cons

- Terribly squishy, even with this setup.

- Mana hungry

Tinker with these if you need to. Its set forward as a defense tree that is strong during laning. Nami is relying on the small utility investment to stop going oom.

Avoid picking nami vs a Draven. Even with this setup she is too fragile and a good one will outpoke and dive you. His laning is insane.

Sona is a hassle too but not as bad. She AoE heals; Nami AoE harasses. She lends MR to her partner and pokes back just as well. Think of it as a stalemate.

Provided you ward I've bet most bruiser kill lanes with nami. Prison punishes dives and ebb and flow punishes their lack of range and sustain.

Wards before item completion, this can't be stressed enough. If you aren't showing the entries into the area where your ADC is farming you aren't a support at all you are just a very slow farming carry. Play the sight war with purples if you are feeling confidant but don't get you and your carry killed just to destroy a ward.

You might have a chance of finishing these items before the game ends. Usually I only finish two, if that. They are: Upgraded boots, Bulwark of the Legion, Twin Shadows, Ruby Sightstone and Shurlia's. The last slot is occupied by wards.