I like to relax into my exhalations whether sitting in meditation or holding a posture or lying in savasana http://en.wikipedia.org/wiki/Savasana. What I mean is to allow them to deepen by relaxing consciously any blocks or tension or constriction. As I finish the exhale I wait for, or allow, the inhale to come on its own... deepening on its own... due to the release of the previous exhale.
When I am trying to consciously relax a specific area, I keep my mind focused on that area and watch without judgment each breath allowing the relaxation to come, never forcing the exhale or sucking in air on the inhale, but just gently waiting and watching.
