I was a technical writer in Massachusetts for 20 years, and then my wife and I retired to New Mexico in 2006. I'd been active in a writer's group for about 16 years and learned tremendously from these friends, some of them published and others yet to be published. They have easily been the single most significant influence on me as a creative writer. Here in the Southwest I have met some fine people and fine writers with whom I also hope to learn and share.
Reading is naturally a big influence, and I try to read good writing in a variety of genres and styles. No one writer stands out as an influence on me, but I remember picking up David Copperfield a long time ago and thinking how wonderful it was--that's after having hated it in high school.
Authors on my current reading list include Brokaw, Gerritsen, Hiaasen, both Kellermans, and a few others. Evanovich, Barnes and Sanders are some of the others sitting on the shelves behind me. Though I don't study these writers, I do try to notice what they do that works. There are some very fine writers to enjoy and learn from.