Alexandra Sokoloff has a great series on her blog about the
Three Act Structure, which breaks down a lot of things I used to create the outline template I use.
A lot depends on the kind of writer you are. Some like a very loose outline, while other like to know every detail before they start writing. Both are perfectly acceptable options.
What I've found the most helpful, is to create a loose outline with the key elements of the story. That way I have a solid foundation under me to write on, but still allow for spontaneity in the story.
My general outline looks like this:
Opening scene
Inciting event
Act one crisis
Mid-point reversal
Act two crisis
Act three crisis
Climax
Wrap up
That gives me all my major set pieces and ending. Then I just write toward each of those set pieces, letting the characters do what they do.
I also do a chapter by chapter summary to get the gist of what each chapter is about. I focus on the goals, motivations, stakes, and what goes wrong to drive the chapter to the next chapter.
If you want more structure, another helpful thing is to also identify what the goal is in each scene, what the protag is doing to get that goal, what goes wrong, and what the protag does next to deal with it. This gives you a plot-advancing outline with one scene leading to the next. Just overlay it with the loose outline above, then break the whole thing into chapters.