Most of the people on here have pretty similar answers, so I won't spell out star ratings individually. But I do have a subtle variance in my approach.

I'll usually go sort of in tiers of evaluation.

1. Personal enjoyment for me (pure opinion).
2. Innate quality of the work within its sphere.
3. Technical competency.

If a book is less than 3 or 4 stars on a given tier, I try to switch to evaluating on a lower tier instead. I want to clarify this isn't necessarily an average, but rather a way to hopefully give books a "fair" rating even if I didn't personally like them, or even if they arguably failed at what they set out to do.

For example, I recently finished two YA fantasy books: Lightlark by Alex Aster, and Kingdom of Ash by Sarah J. Maas.

• Lightlark Is the first book in (presumably) a gestating fantasy series. ultimately I gave 3 stars. For personal enjoyment it was down in the 1-2 stars area, so I started evaluating on whether it was a good YA fantasy book in general or a good book to launch a series. That ended up being like 2-3 stars. Dipping into the technical competency level, I rounded that up to 3 because the writing was functionally okay, if uninspired.

• Kingdom of Ash was the culmination of a long YA fantasy series. Going by personal enjoyment, I would have given it maybe a 3. I didn't not enjoy it, but this isn't really my genre and I was reading it for my wife. So I switched to evaluating on the innate quality of what the work is trying to be, and ended up giving it 5 stars because it's a fitting and powerful end to the series and a great example of broad appeal YA fantasy. As that ended up being an acceptable rating for me, I didn't weigh in basic technical competency to my score.