Outlining?

So my current outline of my novel is going ok so far, and since I don't usually outline, I'm trying to focus on the major points that I want to explore in the story. I have reached the turning point of the first act, which is going to spin it off into the meat of the story, and unfortunately, this is where I'm getting stuck.

What are some of your tips for outlining? What do you find most useful for you when you outline? Major characters? Major plot points? Do you ruin the fun of writing by detailing it so far that there is no discovery to be had when the words flow?