I'd like to share a tutorial I did for NB Hobby & Art (you can find the tutorial here, it's in Croatian but the pictures are self explanitory! :) )
Making your own buttons is easy but it is time consuming but I love making them. I use Fimo (a polymer clay)...comes in so many colours.
A great tip for making this canvas is to use sequins (or gems, pearls) to fill in the little gaps.
And if you don't feel like making your own buttons you can always buy mine! :) Pop bythe Jane's Doodles blog and check out Eva's sweet card! :)