http://harem-battle.club/wiki/Flower.../FKG:Equipment

First you should always upgrade mid-tier (silver) equipment which is mostly warriors ring, earring and above (gold) and always use low tier and bronze ones as fodder. Yeah always (try to) sacrifice 10 equipments at once since its cheaper in the end. Dont bother with bracelets and amulets like i said, just go level warriors ring and earring if possible.