We compare different methods to measure the anisotropy of the spin lifetime in graphene. In addition to
out-of-plane rotation of the ferromagnetic electrodes and oblique spin precession, we present a Hanle experiment
where the electron spins precess around either a magnetic field perpendicular to the graphene plane or around
an in-plane field. In the latter case, electrons are subject to both in-plane and out-of-plane spin relaxation. To
fit the data, we use a numerical simulation that can calculate precession with anisotropies in the spin lifetimes
under magnetic fields in any direction. Our data show a small, but distinct anisotropy that can be explained by the
combined action of isotropic mechanisms, such as relaxation by the contacts and resonant scattering by magnetic
impurities, and an anisotropic Rashba spin-orbit based mechanism. We also assess potential sources of error in
all three types of experiment and conclude that the in-plane/out-of-plane Hanle method is most reliable.