Near the begining jump over the cannon and fall next to the wall underneath. You should get blasted out of a cannon and sent in a cart almost all the way to the end of the level.
Blue Balloons are the rarest items in the game. However, two of them are hidden in Jungle Hijinxs, the very first level. Ride Rambi all the way to the end of the level, but don't leave. Instead, jump on top of the exit and climb to the very edge of the screen. Jump up and dismount Rambi while in midair off-screen. This will give you just enough of a boost to reach a hidden tire, which will let you bounce to a launch barrel. It will fire you into two Blue Balloons, granting you an additional six lives.