Most estimators spend a lot of time in the Tree View screen so take advantage of some of the customization you can do in the way of colors. One way is to add a color block to distinguish between resource types. An example is below:

Easy to do and each individual can have their own colors however I would encourage some standardization for larger Teams. Go to TOOLS>PREFERENCES>USER>COLORS

Note that there is also a setting that if a crew is modified the crew code can be colored so that it will stand out. If you want your settings copied to other Teams members just go up to DISPLAY and there is a “copy user preferences” where you can copy your preferences one at a time to other users.