I've just put the finishing touches to the first draft of a "follow-up" to Red Mercury. It's not a sequel, although it is set in the same alternate history and features some of the same characters.
I really enjoyed putting together my first book, and have been pleasantly surprised by its reception, so I figured another one was in order.
The first draft is now in the hands of some "beta readers".
The worth of getting your drafts read by a bunch of people cannot be overstated. With Red Mercury I got some excellent feedback and comments which helped me really tighten the story up and improve some of the characterisation.
I heard it said that if a reader suggests something is wrong in your writing, they are almost always right, but how they suggest to fix it is almost always wrong. I try to bear that in mind when I receive feedback - whilst the suggestion of exactly how to improve things might not fit with my idea of how the story should develop, the suggestion itself is often a hugely-useful signpost to a patch of writing or a plot element that isn't working.
Aside from all that, it's simply good practice to get a bunch of folks to run their eyes over your prose. Having done this once already, I'd say the hardest part of self-publishing is self-editing. Get as much feedback as you can - from general thoughts on plot and place, through to helping spot those typos.
Once I have gathered the feedback from my brave guinea pigs, I'll get cracking with revising the text. I'm hoping to have the new book available on Kindle and in print by the start of June. I'll keep you updated.