How should I start my chapters?

Be careful about prologues because they often seem like something "before the story starts." They have to follow the same basic pattern as all story telling. If there is no other purpose than introducing the character, I would consider dropping it and working any background you need into the story as it goes along. So wherever you start let it be with something happening. You mentioned you do that with your action stories but it's really the same thing with this. Begin in the middle of something going on. It could be a shock your protagonist gets in a conversation, a telephone call, or seeing something happening she/he doesn't understand. In romance it could be a reaction to seeing the romantic interest for the first time. It needs to be emotional and surprising (at least for the character) but it doesn't have to be all that active in a physical way. In a smaller way, it's the same with chapters. It's best to END each chapter with something that leaves the reader a little anxious about what happens next and begin the next one in the middle of what was hinted at in the last one. Think of a chapter as a complete scene which ends with a "teaser" leading to the next scene. As far as planning, you're right to have an overall goal for the protagonist and it's good to be thinking about some of the points that have to happen to get there but don't worry if, as you write, you find you want to change some or all of those. That sometimes happens as you begin to feel you better understand the character and know how they would react to things. As far as not planning to publish, that might not be a useful way of thinking. If you want to be a writer, you should always be thinking about how a reader would be responding to what you are doing. Maybe you're right and publishing at this point in life is not likely but it's not impossible and you should be working at it the same way you would if you already had a contract and a deadline for the manuscript. Even if you can't get it published (it won't be because of your age but possibly do to lack of experience) it may be something you'll get out in ten years and realize it can be reworked and sold. NEVER LOSE ANYTHING YOU HAVE WRITTEN! Back it up, protect it and keep it forever. I hope this helps.