INSPIRATION won't happen if I just sit here.  If I am not INSPIRED at the moment to do a painting, say for an up coming show or competition, I need to take action.  This is painting time in the studio not goof off time.  So I need to prod "INSPIRATION" a bit.  How do I prod INSPIRATION?  Sometimes by looking at the beautiful work of other artist's one will be INSPIRED.  But, in the past, that usually has lead to a lot of time wasted browsing the pages of art books and magazines.  Then if an idea comes it is usually to paint something along the lines of the fine painting in the book I'm looking at.  For me that is not really INSPIRATION.  In fact I find it depressing.  So here's what I do.  Since, in the studio, I am both the boss and employee (I like that) I'll assign myself the kind of painting I'm going to do (portrait, landscape, etc.).  Then, say it's a landscape, if the weather is good I may step outside and look for an appropriate subject.  Or I will look at reference photos I have collected of landscapes.  I keep in mind NOT to look for the perfect picture, but for something of interest in the photo.  Then I'll go ahead and get started with a loose oil sketch.  Usually by the time I start placing paint on the canvas my mind has been stimulated in the painting process so that INSPIRATION  is beginning to take hold.  If it has not yet I know from the past, if I keep painting, it soon will.  So if, today, you need to get busy painting but are not yet INSPIRED, start prodding.  It's painting time! 
Best wishes, Jerry