This thesis describes method development in TEM-related techniques and their application to the study of nanoprecipitates and low-dimensional structures. The work is divided into two parts. • The first part is focused on the structures of nanoprecipitates found in Al-Co, Al-Ni and Al-Fe-Zr alloys. • The second part describes the effect of accelerating voltage and its direct impact on image formation in different materials including the application of low acceleration voltages to the imaging of graphene single/double sheets quantitatively.