Never mind about "out of sight, out of mind" - the longer you leave the dust under your bed, the more it accumulates. This may be great news for dust mites, but it's bad news for anyone with allergies.
Tuck lengthy dust ruffles and bed covers into the mattress, to give yourself free access to under the bed.
Pull bed away from the wall to vacuum, or pass a damp cloth along runners and behind the headboard.
Vacuum thoroughly under and around the bed, paying special attention to corners of floors and walls.
Sweep a dust mop over wood floors.
Pass a damp or lightly soaped cloth along runners, if you have carpet, or a cloth dampened with wood soap over runners and floor, if you have wood floors.
Replace your bed and repeat every month or so.