There are a number of ways in which you can change the appearance of your spectra. A number of things can be changed under Edit Spectra in the Experiments menu. The Display Options tab allows you to change the colour of your positive and negative contours. You can also order you spectra which will define the order in which they are drawn on top of each other and the order in which their buttons appear in the spectrum toolbar. You can also give your spectrum a keyboard short-cut. The Referencing tab allows to change the spectrum referencing at any point. In the Tolerances tab you can change the ppm tolerances within which Analysis looks for assignment options. This is particularly useful for solid-state NMR, since larger tolerances are often needed here.