Bad habits can be hard to break. We know this as writers. These habits can pertain to the mechanics of writing such as improper comma usage, passive voice, or run-on sentences. Other bad habits can sabotage our efforts to write in the first place. Fortunately, unlike smoking, I think these habits are a little easier to break.
Playing it safe. We don't always take risks as writers and push ourselves--or our characters--to new limits. If we don't, we'll never see what we're capable of. Try writing in a different genre, or in a different style, write characters who scare you, or write about a subject matter that makes you uncomfortable. You can take risks in lots of different ways to beef up your writing and show readers (and yourself) what you can do.
Not setting a writing schedule. I'm guilty of this. Sometimes, I only write when I'm feeling it. Such a lame excuse. Just the act of sitting down and free writing can make you feel it. It's the same when I'm not "inspired" to hit the gym, but when I force myself to, it doesn't take long for those endorphins to kick in and I end up happy I dragged myself out of bed. If we all waited until inspiration struck, we'd rarely produce any work.
Quitting when the going gets tough. It's so easy to say, "Screw it!" when things don't turn out the way we want, or we come upon a difficult scene to write. We oftentimes want to throw in the towel when we start accumulating the rejections, but that's when it's time to either trudge through that difficult scene, or take another look at the query letter. Something may not be working, so look into another way of doing it. Changing up your method or routine can sometimes get you back on track.
Comparing yourself and your work to others. We all have authors we admire and even emulate, and that's okay; we can learn a lot from them. The problem is that we can fall into the trap of thinking we need to be them in order to be respected as writers. Other times, it's easy to get wrapped up in jealousy of fellow writers who are enjoying success. It's natural to get sucked into all of this, but we need to embrace the reasons we're different and start channeling that envious energy toward mastering the craft, as well as our own unique style.
Being negative. Stop beating yourself up! Whether you say it to yourself, or to others, the constant, "I'm never going be good enough," or "I suck," does nothing but create this dark cloud hovering your their head. Plus, it annoys the heck out of those around you. If you think you're so terrible, try to pinpoint what areas you need help in and focus on that area: go to the library and check out reference books, enlist a friend to help read over a troublesome chapter, take a class through the local writing organization. Even getting away from your WIP and trying something new can rejuvenate your writing mojo and cast that black cloud away.
These are just a few of the bad habits we as writers can easily fall victim to. What are some others and how do you just say no to them?