From the first it's daft — it's obvious that it's crazy (7)
I believe the answer is:
idiotic
'crazy' is the definition.
(I've seen this in another clue)
'from the first it's daft it's obvious that' is the wordplay.
'from' indicates an anagram (from the letters).
'the' becomes 't' (the is pronounced as a 't' sound in some dialects).
'first' says to take the initial letters.
'that' becomes 'ic' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
The initial letters of 'its daft its obvious' is 'idio'.
't'+'idio'='tidio'
'tidio' anagrammed gives 'idiot'.
'idiot'+'ic'='IDIOTIC'
'it's' is the link.
Can you help me to learn more?
(Other definitions for idiotic that I've seen before include "Inviting ridicule" , "Half witted" , "Mindless" , "Altogether nonsensical" , "Witless" .)