Hello! Well everybody lines up on main street hours before the start of the parade. However, farther back, in frontierland by splash mountain, it is much less crowded. The parade starts on main street and heads back towards frontierland. I would suggest being over there. People will argue you get a more magic feel to the show up front, by the castle or on main street. To me being close to the parade is more important. Either wait 1 to 2 hours before hand to see it on main street, or 1/2 hour before at the end of the parade route. One thing I like to do is watch the parade from right in front of the castle, up the steps. You are not right next to the street, but your view is much higher up, over everyone else's head.
Enjoy! It is my favorite parade!
-Dan