For more luck jou need the following things equipped:
(sora)sweet memories keyblade(complete the spooky cave(hunderd acre woods))
(donald) meteor staff (seadrift keep chest (port royal))(goofy) genji schield (complete the titan cup (olympus coliseum))
these things have the lucky lucky ability with them
if your party has already the lucky lucky ability equip this too for more chance too get something rare.
for more luck use the:
lucky ring (complete the pain & panic cup (olympus coliseum))
with all of this the items will rain inside (7 times lucky lucky)
maybe you will get the nobody lance and the wizard`s relic(donald)