In the tips and tricks for Shen there is an example that you can use your ult by pressing F1-F4(or is it to F5?).
How do you know who on your team is which F? Does this also work for for using shield, heals etc.?
I know you can use your spell by clicking on the icon of your ally(sometimes useful in TF's, by getting dragons/barons because you can't target them easily).
Is there also something similar to the F1-F4 system to use on enemies (by pressing tab or something?)
This could be useful to use your stun on them, and be sure it would hit them.