Create a main theme for the major parts of your story to revolve around. For example, the main idea of the story is that the leading character is frantically searching for her perfect man, because she desperately wants to get married by her 30th birthday.
Develop a goal for the story. This is what the main character hopes to accomplish by the end of the story. For example, the goal of the story is for the main character to fall in love and get married by her 30th birthday.
Decide what the consequences will be if the main character isn't able to achieve her goal. The consequences of not meeting this goal must be severe enough to motivate the main character to relentlessly pursue her goal, and for the readers to relate to it. For example, if the woman searching to find a husband by her 30th birthday doesn't get married by her deadline, she will force herself to settle for her slimy boss.
Divide the main theme into a three or four different, smaller events. These events should all be separate parts of the book. For example, since the main character is getting married, some main events could be her going out on a series of bad dates, finally meeting the groom, a big fight between her and the groom and a disaster with her wedding dress.
Add ostacles into each part of the story to make the reader believe that the main character might not achieve her goal. This will keep the reader interested in the story, and want to keep reading more. For example, the main character might get stood up for a date that she was excited about, or her wedding dress might accidentally get ruined on the morning of her wedding day.
Find a way to make these events seamlessly transition into one another. Each of the events should have the main character as the center of the story line. Everything should neatly tie together, in order to make the story easy to follow for the reader. When he is done reading the story, the reader should be able to look back on it and see how all of the events worked together to make the story end as it did.