1) Get used to waiting. (That's different than be patient.)
2)Don't get too used to waiting.
Writing is all about waiting. Waiting for the idea to ripen, waiting for the words to come, waiting for the sliver of time in your life to get time to write, waiting to hear from critique groups, agents, editors, cover artists, marketing people, booksellers, and finally readers. It can be exhausting. And discouraging.
The single most important thing I can say about that is - don't get too comfortable with it. Push. Many times I look back and know I should have pushed more. Pushed myself, pushed my agent, pushed for my books. I should have written more (right now I am finally finishing the manuscript of my heart, which I should have done sooner but I was waiting to hear something... anything... from editors).
DO SOMETHING. Even if it's a misstep, taking action will give you a sense of possibility, of power that just waiting for everything to work out robs you of. Write something else. Finish a piece. Create a website or blog. Go to writer's conferences. Learn, learn, learn, about craft, about new ways of publishing, about other writers, about the industry, about your own strengths and weaknesses. Then put what you learn into action. Try. Fail. Try again.
I have been in writer's groups all over the country. I have always been the most published writer in them. I have not always been the most talented writer in them. The biggest difference was that I did something. A lot of somethings. I kept at it.
I think it's summed up in a fortune cookie I got recently: Your ship is safe in harbor. But that's not what ships are for.
The weeks before I got my first book offer I stuck a note up on my bulletin board by my desk that said - If your ship hasn't come in, swim out to it.
Sink or swim. Set sail. Do something. Today.