Before I start almost all of my projects, I make a color copy of the canvas. If the canvas is too large for my desktop copier, I take it to a professional copy shop. The copy is useful for making notes about threads and stitches used and for placement of embellishments when the stitching is finished.
In this case. I am painting out the candy canes. I intend to attach JAB candy cane buttons when the piece is finally stitched, having stitched over the original images.
I use Liquitex Acrylic Artist Color paints because they are very true to color and dry well. They can be mixed to create custom colors and thinned with water for the appropriate coverage. I use either a straw to blow the excess paint out of the holes in the canvas, or an aerosol duster.
Painting out images you do not want or intend to cover with an embellishment is just another way to make a canvas your very own.