What does 形から入る mean?

Question

What does 形から入る mean? What contexts may it be used in? I can't find the phrase in my dictionary.

I ran across this in an anime. Transcription of the relevant parts:

[麻]{ま}[音]{おん}の父さん　「本当にこの子は『漫画家になりたい』言うたり、『ぬいぐるみの中に入る人になりたい』言うたり、あれはいつだったかな」

麻音の母さん　「小３の時ですよ、突然…手品師になるからシルクハットとタキシードを買えって言って」

父さん　「そうだった！とりあえずこの子は[形]{かたち}から[入る]{はいる}からな」

麻音の友だち１　「ははは…なにそれ？」

麻音の友だち２　「夢、変わりすぎ！」

父さん　「まあ、何でもいい。自分で選んだ道だな。麻音が自分自身のなりたいものになればいい」

Translation attempt:

'Really, this girl used to say things such as "I want to become a mangaka", "I want to become someone who is inside stuffed animals"... when was that again?'

'When she was in third grade. She just suddenly demanded a silk hat and a tuxedo because she wanted to become a magician.'

'That's right. Anyway, she ???'

'[laughter] What on earth?'

'Your dreams [of future] are too strange!'

'Well, anything works for us, if it's a path she's taken by herself. She may become anything she wants to.'

Answer 1

Good question. The phrase would drive me up the wall if I were a Japanese learner, too.

「[形]{かたち}」 here means "appearance". What that ultimately means is "outfit".

「[入]{はい}る」 here means "to start (learning something new)".

I am sure small bilingual dictionaries could be useless with these two in this particular context.

「形から入る」 means "Someone (always) starts with the outfit (when taking interest in a new field)."

Fashion over practical training, sorta.

Answer 2

You can practice magic if you have cards. A silk hat and a tuxedo are nothing do with magic. You only need them on stage.
So, 「形から入る」 means, buy a complete suite, or more than necessity, before training. If you give up, it's a waste.