How to tell if someone is low elo
Just ask them what they think of tf. Almost always, low elo players think tf is a terrible champion, they think rank 1 w blue card gives adequate mana sustain. They always talk about how tf gets dominated in lane by LB or zed or whatever assassin. They get angry when he's in a side lane creating split push pressure, always wanting to 5v5. However, the converse isn't always true. Just because someone knows TF is a strong pick doesn't mean that they aren't low elo.