I recently bought 10 new canvases. I didn't need them but they were on sale. I have five 16x16 and five 36x36. Even though they say they are triple gessoed I always do one or two more coats of gesso. My favorite gesso is Utrecht's Professional grade gesso. Then I covered them with gold leaf. The bottom picture is before cleaning and the top photo is after gently cleaning with an old T-shirt on a small sponge.
There are several types of adhesives to use and my favorites are either Duo Embellishing Adhesive by USArtQuest or gold leaf adhesive size by Old World Art. I've also used matt or gloss medium but you need to be sure it is kept semi-wet because once it dries the leaf won't stick too well. The very worst thing to use is spray adhesive. It is bad for you and the environment and besides it doesn't work well at all. Nasty, nasty useless stuff in my opinion.
Now it's ready to be painted on and may bead up a bit with the first coat but keep going and the paint will stick very well. I start with the most transparent paints available. Later the more opaque colors can be added when I'm sure I want to really cover the gold leaf. Why gold leaf a canvas if you cover the whole thing with opaque paint?
I recently drove between Vancouver and Seattle which takes about 2 1/2 hours. This is the perfect time of year to drive as far as the scenery goes. The deciduous trees are turning from the very palest greens to more mature greens which creates a wonderful contrast between the evergreens which are sort of black green and the newer greens seen in the spring. I saw blue-purple lupines, California poppies, burgundy grasses, pale yellow mustard plants and the deeper yellow Scotch Broom. Wonderful blue skies and good views of Mt. Rainier too.