@shaddoth1I hate even suggesting it, but according to Scott King's, The ReWrite, he not only suggests a one-month wait before editing, but also specifies 11 separate review reads of the entire (with NO editing, other than making notes), just to identify your outstanding issues.
I myself have never undertaken anything so strenuous, as once I complete my complete first draft, I'll genuinely dive right in (reviewing, revising, clarifying, adding new threads and expounding) since the first several chapters were completed well over a month ago.
As for switching from one story to another, I also take a slightly different path. Since I find that creative writing and editing occur in opposite sides of the brain (creative vs. analytic), I always work on some story, just to ensure that my edits don't go stale. Whether you ultimately use those interim stories doesn't matter, what does is keeping you creative energies alive and thriving during the tedious revision/editing process.
I'm also fairly good at switching from story to story, so when my main backup story doesn't pan out (which is fairly common), I'll start writing chapters in a number of potential stories, just to see which one comes alive, demanding I dedicate my efforts into fleshing it out.
Otherwise, if the story isn't flowing on its own, I find long walks, after emptying your mind, work best. As long as you're aware of what you need (story wise), simply thinking about other things while taking a long walk, often the ideals will congeal without your having to force them.
gruntsgt:
Find some short stories in a similar vein to what you want to write and read those to get "in the mood" so to speak. Hopefully that will work and might even jumpstart some ideas.
Sadly, though a LOT of writers take that approach, but well-known authors caution taking that approach, as you're more likely to either copy aspects of the story outright, or at least 'try out' certain styles, sometimes producing a Frankensteinish writing style (pieces of several other authors, transplanted onto your own narrative).
Thus, I'd avoid reading within the same genre, for example, other sci-fi stories might be OK, but I'd definitely avoid reading in the same sub-genre).
Just my 2 cents.