On a dark background, position the white letters. I suggest you keep every letter on a different layer so its easier to make changes... Do not rasterize them, otherwise the layerstyles later on will be of less quality.
step 2 of 4
Now add the layerstyle how you like. Many times I forget to use in the Bevel & Emboss the options for contour and texture. They are difficult to tweak but they are quite powerful features. Be careful: for the different sizes of the letters you need different values for the layerstyles! And of course add a drop shadow.
step 3 of 4
Now you have to decide which letter pushes others to the back. With simple layer masks you hide what needs to be pushed back by another letter. You can spend a lot of time on this to get all details correct.