So I've been reading an interesting series of threads on reddit recently, made by a reader for an agent. They discuss how to get an agent, a little about publishing and some of his thoughts about what makes a book/story worth reading. It included one particular idea I found fascinating about putting in a "cat rescue" at the start of your story - a short problem which is solved quickly by the protagonist in order to help pull the reader in and make them invested in your character(s). This is the last post in the series, but it has links to all the others:
Also, I've literally just discovered that Brandon Sanderson has a writing course recorded on youtube. Sploosh!