"It's about consistency, you've got to keep growing and keep that form going, that's really important," Cheika said.
"It's still early days for him."
Cheika didn't see a problem with Skelton's technique but suggested his height meant he tackled differently to smaller players.
"I'm not sure what he's done wrong with his tackling technique, he's just been tackling guys," Cheika said.
"The thing with Whitelock was a little bit unfortunate because he was just trying to get him down on the ground.
"Two guys like that can't really know what the other is doing.
"Will is taller than everyone, so he doesn't really tackle in the traditional style, of getting down.
"He wraps arms around and he goes to the upper body to wrestle guys to the ground a bit more because he's a big guy."
The 32-22 home win over the Crusaders in Sydney lifted the defending champions over the resting Brumbies into first spot in the Australian conference and three points clear of the Canberra-based franchise with three rounds remaining.
All of those games are against teams outside the top six, but NSW can't afford to take their South African leg lightly.
Cheika is on high alert for this weekend's match in Johannesburg against surprise packets the Lions, who have finals aspirations of their own.
They lurk in seventh spot, just two points behind the sixth-placed Brumbies, but have played a game more than all the teams above them.
Cheika is a fan of the Lions, who are coming off a 40-17 away win over the 12th placed Cheetahs, the team the Waratahs play the following week.
"They (the Lions) believe in themselves around their attack, no doubt about that, they are a team that will throw the ball around," Cheika said.
"They will carry hard and they've got great back rowers...a very positive team."
-AAP
