GRANDMASTER PLAYER TRIES SONA MID IN MASTERS | MONTAGE 

It's quite difficult at the beginning; your wave would be pushed in, in majority of match ups. I suggested just to keep autoing the minions non stop to try to match the push, as well as last hit with Q. Once you get 1 item you should be better at wave clearing. You also want to spam Q when the enemy is close by so you can get first strike gold and passive stacks, from that 1/2 of your Q's will hit a minions which is more push.