Update your metadata (song names, album, track number, etc...) and then you can sort by any of the columns on the top. The default is artist which does by Artist then ablum then track number...
As far as being able to arrange the songs in an unsorted, manual way. I don't think it's possible.
Also sometimes I get an album where it doesn't sort by track number. It's pretty random and I think it's a bug with itunes.