That recording sounds good to me.

But it's always hard to tell, listening to a single track in isolation.

that's why the best advice I have ever been given is: USE A REFERENCE TRACK.

No matter what software you're using (Cubase, Logic, Garageband, Reaper), you should be able to drag or import a WAV or MP3 (or aiff - format's not really important) of a song that you really like, with similar instrumentation, into your project.

Flick between it and your own song. It's amazing how often a mix that you thought was really bright and sparkly suddenly sounds really wimpy and trebly by comparison. Or how a mix you thought was really warm and beefy just sounds really muddy and dull.

I've been using some Jack Johnson songs as reference tracks. I hate Jack Johnson's music - I think it's really bland and smug-sounding. But the production on it is top-notch: very warm and analogue-sounding but with a crisp mid and top-end.