Modern readers seem to misinterpret writings by virtue ethicists as self help, perhaps because much of modern "philosophical" discourse is just disguised therapy books. These are descriptive, not prescriptive, when Aquinas says what perseverence means he doesn't tell you what to do to be virtuous, but what the virtue in itself is. Although there are some prescriptions in the Summa (see Ia IIae Q38 as a prime example), Aquinas mostly left the study of the building of virtue to other writers, as it is a secondary matter.

Also, don't shrink away from toil or lack of pleasure- to an extent.