I have taken several workshops where the answer to this question has been simply revealed. You just BEGIN. You don't need a bolt of inspiration or a sign from heaven above - you just begin. Sometimes beginnings are completely covered up by the end product, but think of the beginning as a warm-up. Some idle little something that tells your brain - "Oh, you want to be creative today. Let me see what I can come up with for you."
How do you begin? You can make an art journal page, collage paper onto your canvas, write your favorite quotes, make some marks, or draw a picture on your canvas, like I did here.
These are five 11" X 14" wood panels all lined up in a row. One big doodle later and my brain went into action.
I worked on the background with the panels together at first and then laid out five hummingbirds on the same looooong branch. I'm not sure the long branch really works but the birds are sweet when they are separated. Completed panels below. Can you see the doodle peeking through here and there? It gives your work depth and there is a little secret hiding in the background that you can share with others - or maybe you decide it will be a secret between only you and your work.
Here is a close up - so many tiny little pieces of paper
Here is a quote from artist, Chuck Close about beginnings. I have used it before because I think it rings true for everyone who is intimidated by a blank canvas.
"The advise I like to give young artist, or really anybody who'll listen to me, is not to wait around for inspiration. Inspiration is for amateurs; the rest of us show up and get to work. If you wait around for the clouds to part and a bolt of lightning to strike you in the brain, you are not going to make an awful lot of work. All the best ideas come out of the process; they come out of the work itself. Things occur to you."
If you have a way you like to begin a project, I would love to hear about it.