In short, a good music review is written in an objective style. Generally speaking, it is focused purely on the music or artist itself and is written for a defined audience. In other words, there is usually no reason for the writer to explicitly state his / her own personal tastes, expectations, or projections. It is of course possible for one to make a valid point using such statements, but in most cases doing so is unnecessary and simply lazy or sloppy writing. In fact, the writer should never have to use the first person and rarely the word "I".
As far as writing for an audience goes, one should always do their homework and consider how a given piece of music is perceived / likely to be perceived by their audience. A few general examples of what NOT to do would include:
- Writing about a release from a veteran, yet very obscure band without any background information, as if most people already know who they are.
- Writing about the new Radiohead album like it's their debut release; providing a detailed overview of their career, as if your readers aren't already familiar with their work.
- Writing an intensely negative review about the new Radiohead album with no mercy or balance, as if most people will uniformly share your opinion.
- Writing an intensely positive review about a critical flop (or over-hyping a promising, but unproven up-and-coming act) without providing reasonable justification.
Most importantly, the task of writing a solid album review is much more difficult when the music you're writing about is made not by major label artists in far away cities, but rather by local musicians in your own community. In this case, praise must be warranted or earned. Tell a story that's relatable and enlightening. My rule of thumb is to stay positive without kissing anyone's ass. On the other hand, criticism should be constructive. Negative reviews can and do sting. Furthermore, it's quite possible that one day the band you decide to rip on (or members of that band) might become very good. And if you are seeking press access (and/or a free copy of their album) and they've heard what you've said, they might just tell you to go fuck yourself.