Various services have different ways of naming their mp3 files.
This is the best software I have come across to homogenise and personalise tags, filenames artists etc.
Its free
http://www.mp3tag.de/en/download.html
For instance, a compilation ends up all over the place. Use the Album Artist to name it say Django's Legacy (Various) and keep the Artist as is (Rosenberg Trio), it will then appear as one album on your PC or device.
It does a lot more than this, and lots of cool short cuts too.