When conditions are tough, I look for habitat with alot of edge and diversity, both in terms of topography and type of vegetation. I'll not spend much time in monotypic habitat like expansive sage flats, large quakie, mahogany or other timber forests. Instead I'll search out small pockets of mixed cover in & around these large habitat types. Mule deer like the edges in vegetation types; these areas most often have the most and the best available forage while being close to security cover.
Topography is important too. I'm looking for isolated draws, ridges and small basins - again small pockets of something different. Realize also that small in terms of typical mule deer country might be be hundreds if not thousands of acres. Daily movement for mule deer might be several miles between bedding and feeding areas daily.
Early mornings & late evenings are the time to spot & stalk these areas, using midday to still hunt & scout for sign and pockets to be at early am or late pm.