Prep your hot pressed watercolor paper while it is still attached to the watercolor block.
Although watercolor blocks lean more on the expensive end, they are far more easier to work with. You don't have to stretch your paper with tape or a staple gun.
Simply spray your paper so it is saturated with a spray bottle. Next, take a flat brush and even out the water on the paper's surface. Lastly pick up any water that drips on the sides of your block or table surface with a paper towel.
Let it dry completely before you transfer your image or begin painting.
By doing this it will loosen the sizing in the paper and allow the fibers to relax, which in turn will let the watercolor absorb easier into the paper. If you don't prep the paper with water on hot press, you tend to get a more wax resist reaction.