Spurs meet Manchester United in today's early kickoff.
And on Wales winger Johnson, Frank said: "Of course it’s about winning, putting a team out there that can win, but my mindset has always been to develop people.
"Let’s say with Brennan, it’s about how does he be more positive? What is his position when we build-up? How does he arrive in the box? How is his link-up play? Does he work hard enough?
“That’s conversations, that’s video clips, that’s feedback, constant feedback day in, day out."
Johnson scored 18 goals for Spurs last season, though has battled for form this term.
Frank continued: "First of all, I’ve got 20 players, I can only play 11, then we need some that need to come off the bench. This year we are hoping to play more than 60 games, that’s a lot of games. So that's one thing.
"In Brennan’s case, I think he is very aware of all his strengths. He’s got something that is extremely important, the ability to score goals. Then arriving in the box and also on the counters, that’s a super strength of his.
"So there are a lot of bits I like from him. He is good at producing crosses and playing on the side, he’s tactically a clever player."