Pace is, quite simply, a pain in the arse.
Pace is how fast a story is being told. It's annoying because it's not easy to explain WHY something is paced too fast or two slow. The only way to figure it out, as far as I can tell, is to read a lot of books, then print out your manuscript and read it like a book, noting down the places where the story is getting boring (pace too slow) or you blink at half a year's gone by (pace too fast).
With my last book, 'Season of Secrets', my pace was mostly too slow - mainly because I set myself targets like 'write a thousand words in a day', with the result that I frantically wrote a load of rubbish to meet my deadline. Editing then mainly became cutting, which is a wonderful process - my target then became 'delete a thousand words a day', which is frankly easier and gives one a wonderful sense of freedom as the story emerges from all the dross, shiny and streamlined. I've deleted about 20,000 words from both of my first two books, neither of which is longer than 37,000 words in total.
With the latest book, however I set myself the target of finishing sections - write two sections per week, I told myself. This has resulted in lots of ridiculously short sections, which are paced far too quickly.
I now just need to add stuff - which I have no idea how to do. Aargh! Help would be gratefully received!