Our little darlings, about to start school, can be a problem (5)
I believe the answer is:
pests
'our little darlings' is the definition.
I can't judge whether this defines the answer.
'about to start school can be a problem' is the wordplay.
'about' is an insertion indicator.
'start' means to remove the last letter (I've seen 'starts' mean this).
'school' becomes 'S'.
'can' is an anagram indicator (I've seen 'canned' mean this (canned can mean drunk)).
'be a problem' becomes 'pes' (I can't explain this - if you can you should give a lot more credence to this answer).
'to' with its last letter removed is 't'.
't'+'s'='ts'
'ts' anagrammed gives 'st'.
'st' put inside 'pes' is 'PESTS'.
Can you help me to learn more?
(Other definitions for pests that I've seen before include "Steps taken about nuisances" , "Take steps to troublesome animal." , "Persistently annoying persons" , "Steps (anag.)" .)