William Stafford poems generally tell it like it is. He tends to let images, actions, and narratives do a great deal of the work in his poems and setting often plays a big role. More often than not, the setting is natural or rural—small town rather than big city. Reading a Stafford poem, you are likely to come across lots of town names and specifics about places and people—it isn't going to be ariver it's going to be "Wilson River." Family and childhood are going to make appearances as well.
Another calling card is Stafford's poetic voice. In The Norton Anthology of Modern Poetry, Stafford described his poetry as, "much like talk, with some embellishment" (892). This makes Stafford's poetry sound familiar. It makes it comfortable to read. His poems have a confident, conversational tone, often sounding more like the way specific people speak than like poetry. As a result, a Stafford poem feels more like listening to your cool uncle tell stories (some true, some imaginary) after a long dinner and a couple beers and less like listening to your bongo-playing English teacher at an open-mike night. And Stafford's speakers tend to keep their cool rather than becoming overly emotional or sentimental, even when discussing subjects that are emotionally charged.
Basically, Stafford writes poems without letting poetry get in the way. Check out "A Family Turn" and "A Posy" for just two other examples.