Bad writing

Part of being a good author is not being a bad author. Tautologous though this may sound, I think there is a distinction. There are competent but uninspired authors, and there are inspired but flawed authors (some of whom sell extremely well!). Good writing needs both creativity and technical ability, and a lot of that technique is the avoidance of flaws. Some things that I try actively to avoid, and also those that make others' writing at best tiresome and at worse unreadable, as follows:

• Character inconsistency. People acting 'out of character' and doing/saying things which that character would not do/say is the most cardinal of sins. At all times must every character stay within their own bounds (development aside), and at all times must they be believable as people.
• One-dimensional characters. Finding the balance between this and the above is tricky, but shallow characters who have a very limited range of predictable behaviour can be very tedious.
• Continuity errors, anachronisms etc.
• Cliche. Not all university professors wear tweed jackets with leather patches, not all secretaries chew gum incessantly and speak in a nasal Jewish-American accent, not all villains cackle maniacally and rant about power, but lazy writers don't take the trouble to create characters outside these stereotypes. Also, adding miscellaneous physical impairments, bleeding eyes and so forth, does not add depth to a character.
  
• Focus on the world, not the people. This is especially a problem in (bad) sci-fi/fantasy, where one feels that the author has thought a lot about all the cool things in the world they have created, and the people/lifeforms running around inside it are merely there to wield the Sword of Deity Slaying or fly the VPL-0134 Super Starfighter of Doom. Sure, fantastic scenarios can provide very interesting backdrops for good stories, but they should not be the story itself. People are interesting, made-up things aren't.
• Deus Ex Machina. All the tension built up through the plot is diffused in one lazy magic ending.
• Pace. Things that are not interesting but are necessary take far too long to exposit, or things that are interesting are not dwelled on enough.
• Self-parody. Usually the sign of a long-running series running out of steam, this is a sure-fire sign of a shortage of ideas.