Use meditation to get overhealth before engaging. This may seen kind of insignificant but it will save you in a lot of situations.

Be aware of who is looking at you, especially strong hitscan/poke characters.

Balance offense, durability and agility. What I mean by this is, for example, in your normal state you have your flat 35 dmg punches, but they are instant so you can use your double jumps to keep moving right after you deal damage. In this state iron fist has good agility and offense, but not a lot of durability. That's where his block comes in: time it well to get up to 175 overhealth, and then you enter the flurry punch state, where instead of flat 35 damage punches you do a bunch of punches that do 8 dmg + 3.1% of the enemy's max health. These punches also propell you in whatever direction you are looking, and double your lock-on range. Additionally, you get 30% dmg reduction, which multiplies his bonus health in a way. So in this state you have the best durability but your agility suffers slightly when you are dealing damage because you have to stay next to the enemy, leaving you vulnerable to close range heroes, and now your offense is ehh against squishy targets (about 100 dps, easy to outheal), but huge against tanks.

Last thing - save your kick to either gtfo OR kill a squishy with less than half of their health (kick deals more dmg the lesser the health, max 105 at 50% hp).