the crack of dawn Very early in the morning
have something up your sleeve Have a secret plan or advantage which can be used if necessary
do the donkey work Do the hard and boring part of a job or task
not sleep a wink Not sleep at all
Hang (on) in there Don’t give up
a rule of thumb A helpful, accurate guide which is based on practice not on theory.
‘by and large’ In general; when everything is considered.
‘get your skates on’ (informal, British English) = Hurry up
‘off-the-cuff’ Not prepared in advance (e.g. a remark)
‘bear (bore/born(e)) the brunt of something’ Suffer the main effects or force of something unpleasant