Your spirit sword is the most central part of your kit, and therefore you need to play around it. When you go in for an engage always be sure you pull your sword through the enemy as you will deal more magic damage when you AA plus your W will be able to block AA.

Your ult is basically a huge ****block for the enemy as you can ult anyone on the team and make a sticky situation for your teammate a favorable one. I reccomend using your ult on anyone you can to save them without you dying yourself in the process, unless the one youre trying to save is ultra fed.

Your combo is E then Q then W when your sword lands at you, not before as you will waste some of the time its up, you also wanna get a proq of your Grasp of the Undying as it tilts the hp diffrence in your favor. The only other tip i can give you here is to play shen a lot and get to know what he is capeable of.

You should be able to duel and trade quite good, as you can E for getting behind them and pulling your sword through them, and block right before their first AA. Watch your passive timer as you wouldnt want to go in without your passive as it blocks a medium amount of damage.

You get your first power spike at 3, since you now can pull of a powerfull combo and trade efficently. Your next power spike is when you reach level 6, your entire team gains a lot of power since you now can rescue a member of your team and likely also kill someone. In the late game you should watch our for adc's like ezrael ashe and vayne as they easily can kite you and you cant burst them down. In the late game you should be able to kill most tanks.