One conflict in Tuck Everlasting is the conflict between Winnie and her parents.  Winnie's parents are perfect examples of overprotective, hovering parents.  They give her no space at all.  That's why Winnie is debating whether or not she should run away early in the book.  

A second conflict is an internal one for Winnie.  She has to decide whether or not she is going to participate in breaking one of the Tucks out of jail.  

A third conflict is another internal conflict for Winnie.  She must decide whether or not she is going to drink from the spring that will grant her eternal life.  

A fourth conflict is the external conflict between the man in the yellow suit and the Tucks.  He wants to reveal what they are, and the Tucks want to remain hidden.  

A fifth conflict is the conflict that Jesse Tuck has with his relationship with Winnie.  He's falling in love with her, and he wants to be with her, but he also knows there will be consequences for Winnie if she drinks from the spring.