Luigi is largely based on spacing your arials, ^throw into a consecutive uair is always fun. Use Fireballs to interrupt movement or some recovery's (Fox, Falco, Ike, Pit after he uses his ^b, and ROB). I approach usually with a Dair > nair, into a utilt juggle @ low percents, works on nearly every char and racks up 40%+ dmg easy. Also dthrow into a utilt juggle or usmash is another great dmg builder. After a SH double arial try to follow up with a a,a,a combo since it will often be faster then there grab and give you space. Luigi's bair is something to be feared since he can set up a mini wall of pain and edge gimp a lot a chars with a crap recovery. Use the tornado sparingly since it is easily interrupted. Luigi can kill @ very low percents like mentioned with the a,a ^b or even spot dodge ^b or shield ^b, both i like more since a,a ^b seems 2 get shielded by better players, if ^b isn't your style, spot dodge fsmash (THROAT!) or dsmash, bot are fast and can easily be done out of a shield. Hope I helped ^^b Go Go Wiegi!