LOL! Do you even have to ask? Charged f-smash of course.
Other than that, usmash out of shield is probably the best way to do it, or charged bdacus out of dthrow (bdacus out of dthrow is not actually a combo because they can DI up, but a lot of the times they will still drift towards you, and instinctively air dodge lol). Lots of kill set-ups come from dthrow, so just use that a lot until you see an opening. Uair traps in the air so if you're falling at just the right speed (and believe me it's not hard) you are promised a uair or bair if they air dodged.
Lots of the kills falco gets are based off of reads, but unlike a character like GaW, falco's smashes are fast, and actually has good set-ups so these reads aren't THAT hard. However, it does take some patience and work, so don't randomly use fsmash or usmash.
One more thing you should take note of: falco's dsmash is aboust as fast as MK's, just without the range, knockback and cooldown time, but it's still great because it can punish so many things, so I'd get used to the range of that move, because I occasionally kill with it (see me vs Dan game 3 GF's septemeber monthly last stock).