Contrary to popular belief, being a successful writer is not a solitary pursuit. Yes, only you alone can plop your butt in the chair and pound out those words on the computer, but what happens when you lose your motivation? What happens when you think you're ready to sell that finished manuscript? You need to network with other writers to gain encouragement, set goals, get critiques from knowledgeable sources, find out about the screwy publishing business, and learn which publications, agents and editors are the right ones for your work.
I'm a consummate networker, being an active member of Mystery Writers of America, Sisters in Crime, The Short Mystery Fiction Society, Romance Writers of America, Pikes Peak Writers, and Rocky Mountain Fiction Writers. Through the contacts I've made, I've found markets for my short stories and made connections with agents and editors. And I had to make a lot of those connections, because my novel manuscript was rejected almost ninety times before I found my agent and publisher six long years after I started writing seriously. Without encouragement from my writing buddies, I would have given up long before then. So, don't be a loner!