Identifying Meso compounds
Why don't use the definition just above the image?


  meso-compound
  
  A term for the achiral member(s) of a set of diastereoisomers which also includes one or more chiral members.


Achiral, i.e. the molecule is superimposable with its mirror image. So, if finding a plane of symmetry, or other symmetry elements in the molecule is difficult for you, a simpler method (and according to the definition) might be drawing a mirror image, i.e. all chiral elements inverted



or unchanged but drawn "right-to-left", i.e. flipped



or flipped vertically



.. (just use any of the mirroring methods) and deciding whether it's the same molecule (stereoisomer), by rotating it, in 3D, in your head. (Some internal rotations around single bonds might be needed as well.)

In the first case, the mirrored structure can be superimposed with the original one by in-plane 180° rotation around an axis perpendicular to the paper plane.

In the second case it can be done by 180° rotation around the in-plane horizontal axis.

In the third case it can be done by 180° rotation around the in-plane vertical axis.