Learning how to apply makeup for photos, especially black and white, and how to work with lighting.
When you are doing makeup for black and white photography, think in terms of shades of white, grey and black – it takes a little time to get used to working in a medium that doesn’t require “color co-ordination”! I find that if I squint my eyes almost shut, that it allows you to perceive tonal values better and colors are not as distracting, so you will get a better idea of the intensity of your “colors” (rather than their specific hue) and see if your contouring is appropriate for the look you are going for.
Use your darker colors for contouring – shadowing effects are created by strategic placement of lights, so your shading and highlighting will be applied accordingly.
B + W photography does not tolerate obvious effects, so blending is your best asset here 
* You will still have to do your usual corrective work (under eye bags, blemishes, etc) – corrective work is about creating a harmonious balance between the models skin (or your own if you are modelling and doing makeup on yourself) and subtle contouring – so blend, blend, blend!!!
* If stronger effects are required for a more dramatic look, then it is really important that no hard lines or harsh edges are visible. Your aim is to alter or improve the appearance of you / your model.
* You may have to add intensity to eye makeup to balance the contouring and highlighting.
* Remember, that reds will photograph as dark, so works effectively as a contour, but if you / your model is used to wearing red lippie, you may have to lighten the shade for a softer lip color.
* Try to keep in mind that streaky or blotchy patches in foundation application will be very noticible, so make sure you apply foundation smoothly and evenly. Unless you / your model are blessed with perfect skin, then a heavier base (more like a two-way cake or pancake) is suitable.
As with all makeup, it is about creating illusions, working with each face as a new canvas and utilising the medium of black and white to its fullest by making the most of its variety of values!
I always like to see a polaroid once the shot is set up, that way you can gauge how the lighting is working with your makeup, and see if you need to make any alterations to get the best shot. Lighting varies so much, depending on the photographers vision of the end result, and black and white is a great way to experiment with lighting and makeup techniques – just remember that the harsher the lighting, the less forgiving the medium is on any flaws / mistakes – uneven lines, streaky foundation, careless blending, and inappropriate product selection.
It takes a bit of practice to perfect the black and white makeup, but it is such a beautiful medium to work in because it really emphasises the subtlties of light and shade!!