Assuming you're beyond the basics, Strunk & White's Elements of Style is a classic.  It deals with some more advanced grammar subjects as well as just making writing more crisp and powerful.

I'm an old-fashioned sort; I won't be self-publishing.  I believe in division of labor (it's what pulled us out of the stone age after all!).  I believe that people train and work hard to become agents, publishers, editors, etc., and that they have specialized skills and knowledge and deserve their pay.  I also don't try to sell my own house, cut my own hair, fix my own car.  I'm just that kind of person.  I want to do what I do best (write) and leave the publicity to publicists, the design to designers, etc.

If a publisher doesn't pick up my book, I'll just assume it's not a good fit for today's marketplace, and write another, and try again.  It's not so important that My Words Get Out There that I am willing to forgo the security of a second and third opinion on their quality.

That said, at some point in the future when I'm flush with cash, I may self-publish some self-help stuff that I don't want to make money on and just want to share with family/friends.  Personal experiences etc., life lessons learned, stuff most people wouldn't care about but would still be nice to have in an attractive package.

I have passed the 75% mark in my current novel (first draft).  I can see the light at the end of the tunnel from here!

I ask myself, is this story being told by me, or by my character?  If it's the latter, I use first person.

Once I had to use first person in a short story because there was no appropriate gender pronoun to use for the main character in 3rd.   

Hi everybody!  I've been trying to write 2,000 words a day on my novel.  Am just finishing up week 3, and have amassed 35,800 words or thereabouts.  I am typing this and patting myself on the back instead of writing today's 2,000.  Just FYI.