- Characters. They don't have to be all good characters or even necessarily likable ones, but they should be interesting, engaging in some manner. I can't abide too much whining, pining or melancholy from characterizations. Childish characters grate my soul.
- Plotting and pacing. The entire story doesn't have to be happy, but it should be able to hold interest. Violence and sex mixed into the content deters many readers; not me. I'm an adult, I prefer adult content and I'm not going to apologize for it.
- Prose. The writing should invite the reader, and I prefer adult-level vocabulary. Explicit language doesn't bother me.
- Settings. The environment: the sights, smells, sounds, and touches should come alive and complement the story without dragging it down. I prefer settings to supplement and support the story and characters, not swallow the characters and story (i.e., China Mieville). In historicals, the historical backdrop I would consider part of the setting; in SFF, the worldbuilding would qualify as part of the setting. Forgive my amateur qualifications.
- Enjoyment value, the trump card. Admittedly, I place an unreasonable emphasis on the ending, and it affects my overall enjoyment factor. It's the final impression a novel leaves afterall. I don't care how dark, how sad, how challenging the story is to read in the beginning and middle, I unconditionally prefer satisfying endings. Not a 100% happy ending, but a satisfying one nonetheless. Along with the ending, humor also affects my overall enjoyment (favorably). If the first 4 factors are subpar yet I enjoy the novel overall, I'll give it a positive rating nonetheless. The converse is also true (first 4 factors are excellent yet I don't enjoy the novel overall, I'll give it a negative rating).
1 -- Very poor
2 -- Has some merits, but still lacking
3 -- Enjoyed the novel though certain factors bring it down
4 -- Entertaining, worth a re-read
5 -- The Cream of the Crop in terms of entertainment value, prose, settings, plot and characterizations.