Your goal is to shove the lane as fast as possible ultimately aiming for a quick lvl 2, trading as ezreal can be quite tricky since his range is low, and skillshots can be blocked by creeps. The window of opportunity is when the lane is cleared and creeps are going in, you can position yourself and trade this way. Abuse this by reaching lvl 2 first and zoning them by going past your creeps and using mystic shot to chunk them, if they over extend you can E > AA > Q > AA. Just remember to keep poking with mystic shot and learn to push or leave the creeps untouched before recalling to not miss any exp as well as denying your enemy some exp.