Chronobreak is a potent escape tool, but it can also be quite powerful when used offensively. Don't underestimate its damage potential.
If you can proc Z-Drive Resonance on an enemy champion, it's worth taking risks to do so. The bonus movement speed makes it easy to escape.
Phase Dive's dash is a great tool for setting up Ekko's other abilities. Use it to get double hits with Timewinder or get into position to detonate Parallel Convergence.
Ekko is significantly weaker when his ultimate is down. Watch for the trail he leaves behind to determine if Chronobreak is available.
Ekko's stun zone takes 3 seconds to arm. Watch for the image he creates on cast and try to guess where the zone was placed.
The second hit of Timewinder does more damage than the first; try to avoid it.