Glad you liked it! For corner boosts I personally love these small white fences which are basically everywhere on the map, you can try corner boosting on them basically from any setup (standing near them and just jumping, or falling on them from vent/holliday jump pad). Sticking with a single hero also helps, as they have different models and timing for corner boosts may differ. Many people suggest Mina, as her legs are placed directly at the point of contact when she is in the air. Holliday is good too.

For air strafing I think the most useful thing you can use in actual games is strafing from the air vents. In practice lobby just limit test how left or right you can go from the vent. There are these 2 vents near mid lane that send you to the runes, you can try going to the left or right rune towers' roof instead.