People don't play Lulu as a support? That surprises me for some reason...
When I play Lulu, I play her aggressively. I'll use my skills to make my enemies turn into animals/reveal them with Pix, and occasionally buff my allies (not including ulti-- I spam that on people). when I think they need it. Sometimes I grab a kill (mostly because I forget about her awesome passive) but other times, my score is completely assists.
Since I'm new to supporting, I tend to ask my teammates if I'm doing well in my role and they mostly say yes.
The thing with supporting I find, is that you can't really do anything if your team completely sucks and doesn't know how to take advantage of the buffs.