My most regrettable limitation as a writer is my need for research. I don't mean to say that my research skills are weak. Far from it. I have mad ninja skills when it comes to research. I love it. And that's the problem. I want to cram all of that research into the story.
For example, I lack knowledge regarding police procedures, and yet I write about cops. Specifically federal agents who happen to be vampires. Fortunately, I can pass some of my limitations in knowledge off under the differences between human and vampiric law. Unfortunately, that only goes so far, especially once I bring in the forensic science guys. (Yes, my vampires are high-tech and use forensics to help them catch the bad guys.)
Since my lack of knowledge does impact how I approach a scene, such as a crime scene in which my characters are supposed to make intelligent and skilled observations based on their years of police experience, I have to go to great lengths to either circumvent my lack of knowledge (in other words, I just make something up and hope it sounds good) or I research the heck out of the subject. I can easily spend weeks combing through books, magazines, journals, and websites to gain the information. Once I feel I understand what my characters are seeing and about to comment upon, I will write.
Oh, and for the record, I tend to limit my characters' profound forensic/procedural observations to a few lines, maybe a paragraph or two if dialogue is included. So...yes, I conduct massive amounts of research for little bits of writing because I have no practical knowledge or experience in the field.
I love to discover new and interesting bits of information. However, no one but me is really interested in certain facts. Such as the average human stomach can only hold roughly four pints of liquid, but the average human body holds roughly eight pints of blood. Therefore, all the vampire movies and books in which the vampire completely drains his/her victim of blood in one sitting are scientifically inaccurate. Unless the author/director is willing to explain the differences in human and vampire anatomy (most don't) the blood draining thing is simply overlooked and written off as "willing suspension of disbelief." (But I still know it's not right and completely changes how I read DRACULA.)
I've also been known to get caught up in the research process and forget to actually write. I've had days where I started looking into something "for just a minute" and Point A leads to Point B leads to Tunnel C that leads to Rabbit Hole D and...suddenly it's 4:30 in the afternoon, I'm getting a text message from The Hubs that he's coming home from work, and I've written two sentences for the day. That's when I start to panic. The panic leads to shutting everyone and everything out of my life except for the writing. That's when I write 250-pages of a book in two weeks. Only to have to rewrite most of it later because it sucks.
Because I love to research and can become lost in it, I enforce time limits for myself. I try to restrict my research hours to weekends when I'm not actively writing anyway. (Yes, I take the weekends off from writing unless under a deadline crunch.) Sometimes I will research at night during the week but I try to avoid it and use that time to decompress from the day. If I simply must research something during the day, during work hours, I set a time limit -- usually 15 minutes. I keep an egg time by my computer and set it. The very loud ticking works to keep me focused on the task at hand and when the even louder bell sounds, I back away from the research and continue writing. Most of the time I don't need the full 15 minutes so I'll use the extra to play on Twitter or Facebook. (Hey, ya gotta goof off once in a while otherwise it feels too much like real work.)
Research is my Achilles' heel. My Kryptonite. It's my strength but it's also my weakness. And I don't know that I would have it any other way.