Adult books seem to have just 6 to 8 weeks to prove themselves. I remember when my first (wonderful) publicist told me that I thought, "But I have yogurt in my fridge that will last longer than that." Success seems to be based primarily on sales, and somewhat on reviews, both in the trade publications (Publishers Weekly, Booklist, Library Journal, and Kirkus), and in the consumer publications.
YA and children’s books seem to work in a much longer timeframe – perhaps as long as a year or more. Do you win any awards? Are you invited to do school visits? And how are the reviews? My current (wonderful) editor tells me they pay attention to: "School Library Journal (SLJ), The Bulletin of the Center for Children's Books (BCCB or Bulletin), Horn Book, and Voice of Youth Advocates (VOYA) are all kids-only, and we also count Booklist and Kirkus." Why not Publishers Weekly, for example? Especially since I just got a great review for Shock Point, calling it a "suspenseful tale of betrayal." For kids' books, I think that there are fewer avenues for consumer reviews, especially in newspapers. It seems the rare paper that has a regular children’s reviewer.