Not straightforward in one's approach! (8)
I believe the answer is:
sideways
'not straightforward' is the definition.
I can't judge whether this defines the answer.
'in one's approach' is the wordplay.
'in' means one lot of letters goes inside another.
'one's' becomes 'sides' (I can't explain this - if you can you should give a lot more credence to this answer).
'approach' becomes 'way' (I've seen this in another clue).
'sides' placed around 'way' is 'SIDEWAYS'.
Can you help me to learn more?
(Other definitions for sideways that I've seen before include "Crabwise, laterally" , "Obliquely" , "Not backwards or forwards" , "Askance" , "Movement of crab" .)