Check out the end stats for how many wards you placed in comparison to everyone else on your team. Nobody should have placed more wards than you. Like how is a person able to ward more than the person who has 
especially after getting this 
which has a really long cool down.
Bodhizapha1 votesI mean thats a good start for an idea of how good or bad. Vision is crazy important. I look at assists kill participation, healing done if I am playing a healer. wards are a big one. how many times I died....lots of facets to the support jewel.
Oakleaf Ranger1 voteswell yah I said as an indicator, though it is a large piece of the picture when determining if your a good one or not
redfeenix1 votesIf you want S on support you should not buy sighstone.
Bodhizapha1 votesIf you want S on support you should not buy sighstone.
Why is that? warding is taken into account for the support grade. As a support it is your job to ward...everyone else should too, but a support should be warding constantly.
newbin1 votesCCing the right champion in a gank. Saving the Adc's ass when they screw up without dieing. Knowing when to run to avoid giving the enemy team a double kill.
Reaper Soraka1 votesIf I want to see if a support was good, I check how many wards they killed.
Were they paying attention to when the enemy placed them? You're the tactician, you'd better.
Sukishoo1 votesIndicator if you know proper Grammar.
An vs A