  It is shown, that mechanical alignment can be efficient for suprathermally
rotating grains, provided that they drift with supersonic velocities. Such a
drift should be widely spread due to both Alfv\'{e}nic waves and ambipolar
diffusion. Moreover, if suprathermal rotation is caused by grain interaction
with a radiative flux, it is shown, that mechanical alignment may be present
even in the absence of supersonic drift. This means that the range of
applicability of mechanical alignment is wider that it is generally accepted
and it can rival the paramagnetic one. We also study the latter mechanism and
reexamine the interplay between poisoning of active sites and desorption of
molecules blocking the access to the active sites of H$_{2}$ formation in order
to explain the observed poor alignment of small grains and good alignment of
large grains. To have a more comprehensive picture of alignment we briefly
discuss the alignment by radiation fluxes and caused by grain magnetic moments.
