I find Nair a better starter. Fair can be awkward sometimes since you may have to jump back a bit then go foward with Fair after an Uair/Utilt/Spike. The more Fairs needed the trickier it gets imo.
Usually Uair x2 -> Nair -> (however many Fairs you need to get them to the off stage) -> Spike works on most. Nair -> Spike is an EASY kill chain if you can them near the edge http://www.youtube.com/watch?feature=player_detailpage&v=Z3NRUr5ibEQ#t=377s
Mario, Luigi, and Samus are pretty easy to chain
Usually Uair x2 -> Nair -> (however many Fairs you need to get them to the off stage) -> Spike works on most. Nair -> Spike is an EASY kill chain if you can them near the edge http://www.youtube.com/watch?feature=player_detailpage&v=Z3NRUr5ibEQ#t=377s
Mario, Luigi, and Samus are pretty easy to chain