With the very soft pencil lead about to break, don't work too hard! (6)
I believe the answer is:
dabble
'break don't work too hard' is the definition.
I can't tell whether this defines the answer.
'with the very soft pencil lead about' is the wordplay.
'with' indicates putting letters inside.
'the very soft pencil' becomes 'bb' (I can't explain this - if you can you should give a lot more credence to this answer).
'about' indicates anagramming the letters.
'lead' anagrammed gives 'dale'.
'bb' placed within 'dale' is 'DABBLE'.
'to' is the link.
Can you help me to learn more?
(Other definitions for dabble that I've seen before include "Work with in an amateurish manner" , "Splash with the hands - work superficially" , "Take cursory interest (in)" , "Do something in an amateurish way" , "Splash or engage superficially in (6)" .)