There are advantages and disadvantages to this. If you plan your novel in advance, and stick to the first plan you draw up, you may miss ideas that may make the story work better. Having said that, if you have a good idea and you draw up a rigid plan then at least you know what you are going to write. I had the main idea for Making Headlines in my head and started to write, not knowing how it was going to end. For Let Go I had a beginning, middle and end, and all I had to do was to fill in the gaps in-between. A current idea I am working on has not been planned, I don’t have an ending worked out, and I am finding it fun just to sketch the main characters. Every story is different and it’s up to you how you go about writing it. I would recommend the software program Scrivener as it allows you to write down chapter ideas and rearrange them as you would as if you had a corkboard. It also has character sheets and a whole range of options that are designed to help you develop ideas. I would use Scrivener to write your rough draft, but always export to Word as it has a better spellchecker (although this may be subject to change depending on how Scrivener will update its software).