An even easier way to "calculate" these quantities is to look them up!
Since we only need to fix two variables, you will typically look these quantities up on a table which is grouped by T and P.
The most common -> Steam Tables (See Appendix B)
If you are using multiple different tables for the same component, make sure that the reference states are the same!
Again, the most common is related to water -> an air/water mixture. (This is the only non-ideal case we will consider!)
Since we now have two components (and still one phase) we need to fix three things (again, we will see why later).
Psychrometric Charts fix the pressure and then let you look up the values of interest fixing any two of the other intrinsic variables (T, specific volume, humidity, enthalpy, etc.).
Use tabular data to determine U and H