Here are a series of teachings which really helped me better understand the book of Revelation and end times prophecy. They are by an excellent bible teacher David Pawson, who has often been criticised for teaching against the doctrine of Pre-Trib rapture and once saved always saved.
He does a great job clearly explaining the symbolism in the book, and also breaks it down into three clear secstions... The letters to the 7 churches, then how things will get much worse for a period "great trouble" before getting much better.
When Jesus Returns: 1
When Jesus Returns: 2
The Revelation: Overview
The Revelation: The Great Tribution
The Revelation: The Wedding
The New Heaven and The New Earth