>>5 I have to disagree with that second paragraph. The amount of detail work you do before writing is completely dependent on the writer. Some work better having everything outlined from start to finish while others are more comfortable starting with a vague idea and pantsing it along the way.
You have to figure out which one is more comfortable for you.
>>6 There are a ton of great books, but there are just as many sites and blogs about it. Search "how to write a novel", and you'll come across at on of useful references. Just remember that books and blogs alike are often written from a biased point of view, so be sure to look at plenty of different opinions and compare them to figure out what applies the most to you.
Manga and books should really not be compared when it comes to flow. If the reader needs images to grasp what you're saying, then either 1) focus on creating a graphic novel instead or 2) learn how to describe things. You can always make a novel with pictures here and there, but you need to be able to describe it so they understand without it.