Since the beginning of World War II, Disney Animation Studios went through a kind of economical crisis, with some of its movies not doing so well at the box office. So during the mid-forties, the studio had lost a lot of animators and was forced to produce features with shorter budgets.
The answer was to create what are called "package films". These, as the name implies, are features made up of several short films. Disney had a lot of material to choose from. Some stories were too short to be features, others too long to be individual short films. So the studio made a compilation of stories in four different films: Make Mine Music, Fun and Fancy Free, Melody Time and The Adventures of Ichabod and Mr. Toad.
Make Mine Music was Disney's first feature to come out after WWII. Made of 10 short films based on a musical piece (kind of the same idea as Fantasia), it is really inconsistent. There are some really great stories, such as Peter and the Wolf (an adaptation of Sergei Prokofiev's suite), and some great pieces of animation such as All the cats join in and Casey at the bat. But there are also some really boring parts that could have been scrapped.
I think that one of the best things from the movie is the opening credits. Which, for the first time in a Disney animated feature, are not static.