Some tips!
1. When you reply, say hi to the member, copy and paste their chart and remove the songs you don't like. This way you are letting the person know what you like about their chart. (This is not compulsory)
2. Leave some comments next to some songs, this obviously isn't compulsory but you can if you want!
3. Comment on the overall chart at the bottom, even if it's just saying "nice chart".