Romance is probably my weakest point. I could beta-read one, but I would have to work extra hard on it: M-rated romance, especially. I am not against beta-ing a story with a lemon, though that particular section of any story may see the least amount of edits.
Also, I will not do yaoi unless it is a minor aspect of the story; this would be like a Hiei/Kurama story in the Yu Yu Hakusho fandom where there are only hints of them being lovers. Basically, no blatant yaoi (or yuri, for those wondering), unless it is part of the canon (Willow/Tara in the Buffy fandom, as an example). However, in the latter example, I would prefer not to work on a story where their love is the central theme. As I am a straight female with no real homosexual friends, I am not prepared to try to understand/write about that type of relationship.
A note on OC's (original characters). I love these guys as much as the next person: they make excellent villains and have more potential than regular characters, since the canon characters need to stay as much in character as possible to be believable. However, as I found in my now-deleted first story about Kurama and Hiei visiting a middle/high school, juggling OC's is even more difficult a process than juggling the original cast. Thus, I prefer not to read/write/beta super-OC stories. The hardest story for me to read ever was by a friend of mine who wrote (then rewrote, then rewrote again) an Inuyasha story about a girl named Sora who was the daughter (granddaugher, as the rewrites changed) of Kagome who eventually ended up in feudal Japan and fell in love with Inuyasha (just like her mother/grandmother did). The real pain came into effect when her friends from school all decided to go back in time with her and join on a pointless quest that was reminiscent of Kagome's quest but even more cliche. Then, on top of it all, it seemed like every other paragraph contained at least one curse word (including in narration).
The subject of cursing brings me to my next point. Please, it is absolutely un-professional for there to be too much cursing in a story. Only the characters themselves should curse (not the narrator unless it is in 1st person), and even then it should be realistic. In the Inuyasha universe (I seem to be referencing that mostly), little 5-year-old-ish Shippou should not be dropping the F-bomb (especially if no one notices). It is just rude to the audience, first of all. Also, it sends mixed messages to the audience: in writing, I believe that strong language should be reserved for circumstances when that is needed. (For example, if a character is drunk, angry, in pain, uneducated, or otherwise not at the "top of their game" then it is fine for them to slip out a cuss word. However, if they are going about their every day lives, then unless they act like a sailor, just forgo that entire section of vocabulary.) Besides, it is a stronger sentence to say:
-The doctor ignored the slew of curses from his patient's mouth as he re-set his broken arm.
...Than it is to say:
-'F***! That hurts! S***, do you have to...? OW!!!' the patient screamed as the f****** doctor re-set his broken arm and ignored his cries.
The first one is much more descriptive than the second and has a stronger focus on the doctor (who is the one performing the actions), and it is much shorter. Also, notice the use of f****** in the narration: that is what irks me the most. The narrator should be unbiased (unless in 1st person) and thus should never ever ever use strong language to refer to someone or something. If I saw that in a story I am beta-reading, I would change it, no questions asked.