Listen to the concert with as much concentration as you can. Some critics make notes, but it can be hard to do this without distracting other concertgoers or the performers, which you simply mustn’t do. Others simply rely on their memories, and you may find this easier.
If it’s a work you know, listen out for anything unusual: is the performance faster or slower than you expect, or louder or softer. If it’s different from what you’re used to, do you like it this way? Do you think it’s the way the composer would have wanted it? Try to remember anything that sounds particularly beautiful, or exciting, or any moments that feel special – a particularly grand climax, say, a specially magical hush, or the way someone lingers over a tune. Try and get a sense of how the rest of the audience is responding, too. Is there a real sense of excitement – or is everyone bored stiff?
After the concert
Think over your reactions. Was the concert a success? Did you feel you’d enjoyed or been moved by the performances? Which bits stick in your memory as particularly special? Did one performance in the concert stand out from the others? Or was one a disappointment? Try and put your finger on why – you’ll need to explain this to your readers
Writing it up
Try to do your writing the day after the concert (or the same day if it’s a matinée): that way, it will be fresh in your mind.
Don’t be shy about expressing your views, but unless the whole thing was dreadful from beginning to end, be constructive. Real performers, even great ones, make mistakes (that get edited out on their CDs), and it’s easy to get trapped into mentioning all the smallest errors and bad parts, and lose the fact that the vast majority of the piece was played beautifully. It won’t make you sound clever, and won’t make for an interesting review.