The journey begins

The first part of any journey is to know where you are going. A goal. To get there you need a map, compass or a really smart guy who knows the directions. Design a character guarding the map or a character who knows the way. If you have to go get a map, you'll need a theif. If you're looking for a sage, you have to know what he wants in trade for the information.

Perhaps the sage wants his lady love to visit so he can tell her why he disappeared. Perhaps he's dying and wants an apprentice. Whatever you decide, the sage needs a motive to tell you what you need to know.
If you need to recruit a thief, he needs a motive to join you. Perhaps he has a chance to clear his family name, or collect whatever treasure is with the map, gain bragging right among his friends or be initiated into the guild of theives.

Stealing a map implies someone is guarding it. This character also needs to be designed. A dragon would not be interested in a map, but might like a nice shiney compass. Someone who collects antiquities might like a map, or someone who wants to trade it might even suffice. You may meet characters who want to join but can't add to the success of the journey also. Whether they join or not depends on the personality you gave to your leader, but if you include them, they will need to have a part later, such as shock troops at the final battle scene. They have to have power motive, but they don't need much personality. Just something like 'the antagonist wiped out their village would suffice.

Your map should have a section where this part of the journey ends, the mountain top or cave under the waterfall, whatever you decide. It should be somewhat secluded, but not secret.

In addition to your characters, at least 3 at this point, you should have on your outline a a paragraph about how the protagonist finds out about the problem, It should be a big problem such as save the kingdom, what needs to be done to fix it, (the goal) and the plan.

In the Hobbit, the problem was brought by Gandolf, who also has the position of omniscient narrator. (I personally don't like the omniscient narrator positions, but it's your story.) You could also use someone returning from their own journey.

The goal was to destroy the ring in the volcano in which it was formed.

The first step was figure out what all the strange people were doing inviting themselves into Bilbo Baggins' house. You could also present the problem as something out of kilter in an otherwise steady world, such a when Yoda senses a disturbance in "The Force", in the Star Wars series. This is much more fun to me to collect characters as necessary.

The sage can't sell his information, but requires something the group has to make a side trip to obtain, or his past love doesn't want to see him or she has died.

Your antagonist will not come into play until you pass the first part of the journey which may or may not involve a battle, but must involve a minor conflict. The dragon can be tricked, or he's not intelligent so that he is easily defeated perhaps the towns people distract him while the theif sneaks in.

Each section of the journey must be harder than the last. By the time you reach the ultimate battle sight, your forces must have enough experience working together to defeat the antagonist despite his overwhelming numbers. You will need an army, but you will also learn his weakness during some part of the journey.

This has been an interesting study for me. If I get any feedback, I'll write more. Feel free to add, or to ask questions. Or, if I'm way off base here, let me know.