Run parallel programs in an HPC environment.
Use a compiler and to assess the effects of optimization switches available for compilers commercially available (e.g. PGI, NAG).
Use efficient open-source libraries (e.g. OpenBLAS, FFTW) or highly optimized vendor libraries (e.g. Intel-MKL, IBM-ESSL).
Configure the relevant settings (e.g. by setting compiler and linker options), which determine how the application ought to be built with regard to the parallelization technique(s) used (e.g. OpenACC, C++ AMP).
Use the profile guided optimization (PGO) technique.
Use software building environments like Scons, Waf, make, Autotools, CMake.