How do you make a photo out of words using photoshop like the 51st Grammy promo photos?

Take your portrait, duplicate the layer and posterise it at the lowest level, this will give you simple tonal separations. Cover the darkest portions with your type (I would use Illustrator for this but you could do it in Photoshop). Once filled, you can turn your posterised layer off, desaturate and reduce the contrast of the base layer and colourise it (in the case of your example with a red to blue gradation), then switch all of your type layers to multiply.