Discovery Writing pros and cons
The best feeling when discovery writing is when the characters you have written, end up writing the stories themselves. The goals and actions stem from the characters themselves, and not you, the writer. This sounds a bit strange and hippy dippie but it is a true technique and if you've ever given it a try, you probably know what I'm talking about. Discovery writing is sitting down and just writing the story as it comes to you. Almost like a structured stream of consciousness. This is in contrast to writing by outline, wherein you typically write down your beginning, middle, and end and some important bits in between, and the bulk of the work is filling in the gaps. Discovery writing is much more organic. I usually already have a loose notion of my beginning and end, or at least the kind of story I want to write and then I just start typing. And every single time, the story takes on a shape of its own that is usually not what I intended when I started, but is actually much better.
The pros of discovery writing is that it can take you places that you never thought of. You are discovering the story at very nearly the same time as your character, which almost makes your writing feel more authentic. It also allows you to get into writing very early and very quickly. Depending on the length of the work, outlining can take several weeks of work before you write a single thing.
Discovery writing really puts you in your character's shoes. It makes you intimate with their wants, needs, and motivations because your choices will naturally stem from that.
It's also very good if you only have a vague idea of a story you want to write. Just start writing and see where it goes. Maybe you don't care if you write a mystery, or an adventure story. Maybe you don't care if it's a short story or a novel. Just write and see where it takes you.
Of course, the lack of structure can also be its downfall. If you're writing a major epic fantasy, that's a lot of information to keep in your head as you go along. An outline, in that case, may be completely necessary and helpful.
The other downside of discovery writing is that it can take you too far in the wrong direction. Stories can lose focus if you try to chase down everything that happens in your head.
If you write for long enough, you'll probably end up adopting a hybrid technique where you outline just enough to give you structure, and discovery write all the parts in between. How much you do either, or in what proportion that works best for you and your particular story will vary.
Try this exercise. Take any idea for a story you can think of that has a beginning and an end, and I want you to discovery write the first chapter. Don't plan plot points. Just start somewhere and see where it goes. Live in the moment with your character. What do they want? Where do they want to go? Why do they want to do the things that they do? And share your results!