When I write, I tend to rely on vision, touch and hearing.
This helps me conceptualize the world my character experiences. I imagine the hazy sky as she tramps through the woods in the early morning and the way the long grass brushes against her legs as she walks. I can almost hear the rustling of her clothing and the birds calling to each other in the distance. By imagining myself in the situation, it's usually easy to find ways to describe sounds, sights and what my character feels.
I find I'm less likely to think about tastes and smells without remembering to work at it. This surprises me, since smells and tastes are a huge part of my life. I'm usually the first in my household to notice the reek of the garbage or the soured milk.
Have you ever examined your writing to see which of the five senses you include the most when you write? Which one(s) do you have to work at?