1. Why did Captain Jack Sparrow refuse to sail into open sea in The Deadman's Chest?
2. Why did Dumbledore leave the infant Harry Potter with the Dursleys?
3. Why did Shakespeare's Hamlet fake insanity?
4. Why did your main character do whatever it is she did in chapter one of your WIP?
Can't answer #4? You've got a problem.
Every action your character takes, every word she speaks is because of something. If you don't understand the because, your character will be nothing but a flat, one-dimensional cliche.
Motivation leads to choices. Choices lead to action. Those actions lead to more choices which lead to more action. Without the initial motivation driving a character's choices, all you have on your page is a string of loosely associated actions that don't resonate with the reader because your character has no emotional stake in any of it.
Let's look at my pop quiz.
#1. Because Jack Sparrow was afraid of the Crakken, Davy Jones' pet sea monster charged with devouring Sparrow and his entire ship, he ordered his men to keep as close to the shore as possible until finally beaching the Black Pearl on an island. That choice pushed Sparrow into another dilemma (facing a bunch of islanders who thought they should sacrifice him to release him from his fleshly prison). His choices during that dilemma would push him into the next.
#2. Because Dumbledore wanted to protect Harry from growing up with the burden of fame and high expectations leveled on him by the wizarding world, he left him to grow up with the Dursleys. His choice insulated Harry from the wizarding world but also left him friendless, neglected, and unloved. His choice helped shape Harry's character, both its strengths and its weaknesses. Also, his choice meant Hagrid had to rescue Harry from the Durleys to bring him to Hogwarts.
#3. Because Shakespeare's Hamlet wanted to formulate a plan to avenge his father's murder without anyone taking him seriously, he chose to fake insanity. His choice fractured his relationship with his mother, hurt his girlfriend Ophelia until she chose suicide over his seeming rejection, and took over his life until at the end, he could barely distinguish between the act and reality.
#4. Because the guilt over her parents' murders and the burden of her supernatural skills drive her to do whatever she can to protect innocents, Alexa delivered some vigilante justice on the streets of NYC one Monday night. That choice led to her being late for a blind date (not a big deal), and landed her on the radar of her best friend's brother (and the man of her dreams) who happens to be a cop. (very big deal)
In each case, motivation is the key to setting in motion another chain of events. When you know your character's motivation and you communicate that clearly to the reader, the conflict makes sense, and everyone has a higher emotional stake in the outcome.
As you write, examine each action, every conversation, and ask yourself why your character is making that choice. If you don't have an answer, neither will your reader.