Have an idea that may be on track, or may be totally off:
Perhaps we are looking for:
GUILDENSTERN or possibly GUILDENSTERN AND ROSENCRANTZ, or perhaps more generally as a directive to HAMLET himself, who Guildenstern and Rosencrantz are trying to get to "Pay attention!"
Take the helm,
STERN is a synonym of HELM; take the stern, alluding to GUILDENSTERN
('take' perhaps also alluding to 'work' and thus to 'guild')
A synonym of 'be present' or 'please focus' is: "pay attention!" Guildenstern and his cohort Rosencrantz were summoned by King Claudius in the play Hamlet to distract him from his current madness. Hamlet was lost in his madness and they wanted him to 'be present' and divulge the source of his woes.
In Hamlet's well known speech to them, we see how he is not present:
Hamlet: "I have of late, (but wherefore I know not) lost all my mirth, forgone all custom of exercises; and indeed, it goes so heavily with my disposition; that this goodly frame the earth, seems to me a sterile promontory; this most excellent canopy the air, look you, this brave o'er hanging firmament, this majestical roof, fretted with golden fire: why, it appeareth no other thing to me, than a foul and pestilent congregation of vapours."
remove your bib,
This is a reference to fencing, removing the bib, or mask. Definitely relevant to Hamlet who does plenty of fencing in the play and hides behind his mask.
and do not blink
Refers to staring, or watching closely. Guildenstern (and Rosencrantz) was recruited by King Claudius to be a spy and watch Hamlet closely.
for the Dane is coming
In the play, Hamlet is known as "the Dane"
and you must have your witz about you.
Guildenstern had his cohort Rosencrantz at his side, aiding his efforts. Both are witty, and I think 'wiTZ' clues 'rosencranTZ'.