I play aggressive safe.
Unless I'm Karthus/Zilean. Then it's just suicide rush.
Lux, I play super aggressive in lane as she harasses really well. In teamfights, stay in the back, throw out all your spells, and try to use your laser to hit all enemies instead of saving it to kill one straggler. Dealing 4000 damage total to all enemies and none dying is better than 500 damage to one and killing him.
EDIT: Also, I got all day today to rush for level 30, anyone want to help?