Thabo Senong's charges lost 2-1 to Japan in the opening match, before being outplayed by Italy on Wednesday.
“Qualifying for the tournament was an achievement, but we need to learn to prepare properly for these events which we didn’t do,” Bartlett told Goal.
“We can’t put a squad together weeks before the tournament and expect them to perform. We need continuous development of players and monitor these players wherever they are playing,” Bartlett said.
“We need to prepare for tournaments well in advance not a month or week before the event starts because it’s not enough. They need more intense preparation in future,” Bartlett added.
Amajita will take on Uruguay in the final match of the group on Saturday.