Research can be bad too. I mean, it's good to know things, but like some guy once said, "He who fights with monsters might take care lest he thereby become a monster. And if you gaze for long into an abyss, the abyss gazes also into you."
Blue Star deals very heavily with death. Very heavily. And I want my deaths to be as accurate as possible, because that's stuff I can't make up, and I just can't allow myself to write stuff like that without doing a little research. Or a lot, as the case may be.
What research did I do? Let's see. I researched a little on asphyxia--mostly how easy it would be to hang or suffocate yourself--and a bit on what happens when you get hit by a train; a bit on shotguns (this is also where my Berkowitz research came into play; Google "Son of Sam" if you don't know what I'm talking about) and a bit on poison (Wikipedia and this were very helpful here), and then a whole mess about sarin and carbon monoxide (CO) poisoning. Frostbite and immolation, too.
No pictures, I can't do pictures. Text can be gruesome enough.
I'm going to give a shoutout to my good online friend Alberic here--she helped me out with some research that I was too squeamish to do--namely those pictures. I remember her comparing someone's head who'd been shot with a shotgun to a banana peel. So if you can't do all the research on your own, get some help. It's awesome.
Did this all help? Yes. Immensely. Some things you can imagine easily enough (stabbing, bludgeoning) and some things need research to be accurate. I like being accurate, so the research was needed. But it can get into your head, too. Thinking about death all the time can have some pretty intense mental consequences, and it's here that I confess that I had to stop writing Blue Star for a week or so just so I wouldn't be thinking about poison and suffocation and just what the body does as it's dying. And it did wonders for my mood--I was happier and more upbeat almost instantly just thinking about a different idea, world, and all that rot.
Mood can affect writing, yes. If you're happy you write happy stuff, and you write dark stuff when you're down. It's why a lot of artists say they need to have some kind of inner turmoil to create the good stuff. But the reverse is possible too; writing can affect your mood, and getting immersed too deeply into what you're writing, while it can be helpful for making the story real to the reader, can also affect you a lot more than you'd like to think.
So watch out, and learn to recognize when that slope gets slippery and you have one foot into the abyss.