Revamping Older Songs (ie Angel)

[gafuller 1,655]

So I'm looking for advice, help, or whatever on an issue. I'm making a compilation called Veni Vidi Vici, but I'm wanting to use some songs from her early albums that have not been redone since their release. I've been using Audacity to working with mixing and editting music for a year now but the thing have yet to fully understand is reworking old untouhed song up to current music standards. Take Angel for example. I can boost with bass, treble, and even amplify but they just don't sound like what we get in Celebration when they revisited older songs (when they did it right that is). Anyone know how I can restore, or whatever you want to call it, old songs and get them sounding fresh?