How to start Writing; A Note
Imagine the scene before you imagine the characters. Thinking of what they are will fuck you up when you're trying to express who they are.
Let your characters express themselves sometimes; as they develop, they are people too.
For those who do plan, character names aren't as important as you think. I got ⅔ through my second book and decided to change all the names, all of them. They're not set in stone. They can change. Unless they have a specific meaning, a joke, pun, or foreshadowing towards the plot (and it's vital, to you), it's okay to let it change.
You can only plan so much, my friend. Eventually, you will get to the point where you'll feel like living up to your own expectations is impossible. Some people need to plan out their whole book(s) and follow it to a letter, but not everyone is like that. If you get to a point where you're content in your planning, and you keep going, you've already started doubting yourself.
Try writing bloopers, little cut scenes in between scenes like a movie. It will help you set a voice in your head, get to know your characters and how they interact.
You don't have to write in order. You can write the end before you write the beginning. You can write little scenes that eventually make up your body. Just keep your ending in mind, even if it changes.
Remember, nothing is set in stone. Your mind is as free and flexible as any naturally occurring entity. You cannot force it into any set slab of stone or granite. It was created free, and trust me, it's not so kind when it's caged up with deadlines and expectations like an animal.
Set a date. Make a time to start and try to make a schedule that you can loosely reference as you get more comfortable.
Don't fret at the beginning. You will grow into it, grow with it, or grow to improve it.
Same with the ending, if it is not flowing, you have not laid a clear enough path. Go back after a full night's rest, or even a week's break entirely, and come back with fresh eyes. Find your plot holes, ask questions even if you believe you know the answer. Eventually, you'll notice a space where the stones are too far out.
Take breaks
Trust the process, and remember,
Practice is progress. Perfection is a concept.
Even the greatest novels have typos, printed thousands of times over. Even your favorite authors have had slumps.