I tend to write action, because I'm utterly hopeless at writing comedy, and I hate writing tragedy. I can do romance if people don't mind dramatic, action-filled slow-moving romance, but on the whole, I think my niche is action with a sprinkling of adventure and only a dash of drama/romance/fluff.
I have trouble writing anything short. I also have a terrible time updating anything, even if I've finished writing it. I just never seem to get around to actually uploading it like I should.
I write mostly yaoi/BL/shonen-ai and gen fics with no pairings. I've only written two yuri/shoujo-ai fics, which I haven't posted anywhere because they're not finished and only one het fic. --long sigh--
I have a lot of fandoms I dabble in, mostly manga/anime, but also in a few other places, like Harry Potter and Smallville (albeit only in crossovers). I've done the bulk of my work in the Yu-Gi-Oh! and Naruto fandoms, with a bit more in the Katekyo Hitman REBORN! fandom. I've also been trying my hand at RPS, and the last NaNoWriMo project I did was 50k words based around KAT-TUN (the J-Pop boyband)...which I've never actually posted because I still haven't gotten around to editing it yet. --droops--
I like reading fics with a happy ending, even if the journey is rough and painful. If ot's a tragedy-fic, or a deathfic, I'll avoid it unless it's been rec'd to me, or is written by a favourite author.