I recently posted on four suggestions from Peter Mead on planning a preaching series on a Gospel book. Peter has now offered four more helpful suggestions. They are,
Decide how many messages the series will last, then select accordingly. You might only deal with a part of the gospel (such as the Upper Room Discourse). You might select exemplary units that point to the flow in which they sit (such as Luke 19:1-10 with reference to the preceding flow of stories). You might choose to preach larger chunks in order to cover the whole text in some way.
Commit to learning the theology and terminology of whichever gospel writer you are preaching. Try to preach John in John’s terms and emphasizing John’s theology. Luke has his own distinctive set of vocabulary. Mark has his own style. Try to let the details of the messages reflect the book from which they are taken.
Preach the gospel you are in, not all four. Use cross-checks in a gospel harmony only to make sure you see what is emphasized in your focus gospel, and to make sure you don’t preach historical inaccuracy. Avoid the temptation to preach the event rather than the text (the latter is inspired).
Try to plan the series to consistently reflect the uniqueness of the gospel. For instance, Matthew alternates between discourse and narrative sections – you might alternate messages from these sections (samples from within the two or three chapter chunks, or overview messages of those sections).