So, my current understanding is that yoniso manasikara is the antidote to grasping any signs and features of the sense spheres. It is inappropriate attention that finds something to grab or to reject in the environment; this day is just today, but "today is Monday" begins to get freighted with all sorts of additional features I might grasp: first day of a work week, and so on. Indeed, "first day of the work week" is, again, a certain feature which I can overlay on top of the given fact of any particular daylight period (but it is no good to try to destroy the function of perception; the problem is not signs and features, but the grasping).
As the Suttas say, some brahmins strove to perceive night as day & day as night, but the Dhamma encourages us to see night as night, day as day. See things as they are, including any proliferations. The goal is not to cease sense function or to blunt a sense sphere such that it ignores input, but rather to see all sense spheres in operation in order to learn and see anicca, etc. The senses are not distracting, it is grasping which makes for distraction (a loud noise which interrupts a conversation can be left behind quite easily, yet it often suddenly becomes, for a moment or two at least, the new topic of conversation with much "halloo" and "oh dear" noises). So, it is not a strained, concerted focus nor a lazy, free-form flow which guards the sense gate, but a voidness where once there was agitation and a perception of personal stake.
One thing to watch out for is passivity; right effort demands that we shepherd the mind away from unwholesomeness the way a herdsman would shepherd their cows away from crops, not simply note "ah, the cows are in the arugala" while doing nothing about it. If the cows are in pasture appropriate to them, then awareness need only be maintained to the extent that "there is a cow herd" (or "there is a body") lest they start to wander (papanca-sanna-sankha).
This sort of practice can be maintained throughout the day, and forms as necessary a backbone for seated meditation as does Sila.