I agree with what you wrote MA. I don't do this in all my critiques but some things that help which I will repeat from your post include.

- Use words like IMO (In my opinion)
- Use emoticons to clarify meanings and AVOID sarcasm unless you know the poster. Sarcasm is a big problem on the Net and is often misunderstood.
- Be diplomatic and EDUCATE. Let's face it, occasionally we see images that we agree are beginner images with common mistakes. Politely suggesting what can help the image is the best way to help people learn.

Thanks all!
Marko