How to play Lux "Support"
Skip sightstone for 5x 
and a 
.
Don't even put a point into bind.
Always farm the wave early to buy more 's.
Take 
.
Always stay way back so enemies can't even see you. The only ability you should use is R to try to snipe enemies with 5%hp or less in teamfights.
Remember to brag about how much damage you do compared to the "adc" in all chat at least twice a minute.
This is standard, I have seen 100% of Lux "supports" play this way if you play any other support any other way you're obviously bronze.
