Peter Mead has some good advice for planning a preaching series in a Gospel. His first four points are:
Get to grips with the gospel before you plan the series. Some good study in a gospel will give you a sense of the flow and structure, of the big themes, the major chunks and so on. This will all help to plan the series creatively.
Recognize that individual units are strung together to make a broader point. As I presented here recently, Luke 18:9 reaches on through 19:10 at least. Seeing how these units work together will help to understand the larger sweep of the book.
Wrestle with the flow of the whole. John’s themes of the deity of Christ, belief and life, recur throughout the book of signs, culminating in the climactic miracle of the raising of Lazarus. Mark’s two overarching questions of who is Jesus and what does it mean to follow him control content throughout the gospel. Once the disciples finally recognize and declare who Jesus is, they discover that they cannot have the Messiah without the cross – so in the end it is the climactic statement of the Centurion that pulls it all together. Try to relate the parts to the whole so that the series has evidence of unity in the way it is presented.
Consider giving an overview sermon at the start and/or end of the series. This can really help listeners to see the flow of the whole and orient them to the message of the book.