jeff ronk - author
Mark starts off running: he skips Christmas and heads right for Easter. as Jon mentioned in his intro, Mark moves. it is a book of action. observe how often he uses the word "immediately". there are very few extended teaching sections- no sermon on the mount, no extended upper room discourse as in John, no long section of parables as in Luke. the teaching that Jesus does in Mark is largely precipitated by questions related to his actions. (this is a broad generalization). in it's organization, the book generally follows a geographical outline- Jesus moves from Galilee, south to Jerusalem. in addition to this geographical change, the focus of his ministry becomes the disciples rather than the crowds. (broadly, this is true of the other synoptic gospels- that is, Matthew, and Luke)
Mark 1:1-13 (15?) is his own snappy intro. Mark starts by putting Jesus into the context of prophetic fulfillment; he also begins to set up some expectations about who Jesus is- "this Jesus- there's something different about him." Mark provides some supernatural witnesses to who Jesus is. this intro is a teaser: he throws out some expectations that will be fleshed out through the rest of the book.
so, with these thoughts in mind, here's the breakdown for the intro:
1:1-1:8 the coming of John
1:9-11 Jesus is baptized
1:12-13 Jesus tempted in the wilderness
1:15-16 Jesus begins his ministry
we will hit each of these in turn.