If you want to rise more in rank i would consider dropping sona. She just isn't good at playmaking compared to others (i.e. bard, blitz, thresh, zyra, nami). All she has is her ult, so if you use it and dont kill anyone then your teamfight is set so far back for like 2 minutes. Thresh and blitz have hooks. Bard has long range ult, good mobility, and to 2 man stun. Nami has a heal, stun, damage buff, aoe knock-up. Zyra does crazy damage.
I main bard and thresh. Then i play nami or braum if the situation demands a good tank or sustain.