Here I am going to talk about a technique i have been using for a while now (mostly in painting) but can be applied with drawing as well. The technique is to take your already existing white surface and apply medium/paint to it to change it into a neutral/grey color/value.
There is a a few reasons for doing this :
When using colored pencil, this grayed down surface allows me to use my white pencil crayon – Now, not applying white onto white, but white onto a darker Grey surface that i have prepared
To prepare the paper surface i find water color works fine for this. Simply take out some water colors and proceed to stain the entire surface, giving the entire page equal coverage – I tend to mix opposite colors (blue/orange – red/green – purple/yellow) or even browns to get colors that are not to bright.
What I find is now when you begin your drawing on a grayed down/neutral, surface (this case paper) you are starting somewhere closer to the middle of the value spectrum as opposed to, at one extreme with working directly on white.
Here are two examples of colored pencil drawings
Blue cups done on white paper.
Orange water done on colored paper.