• All data in a variable must be of the same type and should have the same units of measurement.
• A variable's attributes should be applicable to all of a variable's data.
• A "worst practice":

    dimensions:
      time = unlimited;
      station = 100;
      param = 3; // 1 is temperature, 2 pressure, 3 rel. humidity
    float data(time, station, param) ;  // Don't do this!
      data:units = "celsius, millibars, percent" ;
      

  Instead do this:

    dimensions:
      time = unlimited;
      station = 100;
    float temperature(time, station) ;
      temperature:units = "celsius" ;
    float pressure(time, station) ;
      pressure:units = "millibars" ;
    float relhum(time, station) ;
      relhum:units = "percent" ;
      

• Use 4D spatio-temporal coordinate systems in preference to 3D and 3D coordinate systems in preference to 2D.
• Vector valued (e.g. wind) variables can use an extra dimension for the vector component, versus putting each component in a different variable, but the latter approach is consistent with CF standard names, for example:

    dimensions:
      time = unlimited;
      station = 100;
    float uwind(time, station) ;
      uwind:units = "m/s" ;
      uwind:standard_name = "eastward_wind" ;
    float vwind(time, station) ;
      vwind:units = "m/s" ;
      vwind:standard_name = "northward_wind" ;
      

• Think in terms of complete coordinate systems, and organize your data into variables accordingly. Many applications need variables to have the same coordinate system to be visualized together.

2008 Unidata NetCDF Workshop for Developers and Data Providers > Best Practices