Have a look at the image.
Is is a photograph? a painting? graffiti?
- Find out the topic: love, summer holidays, shopping, family life, school days
- Say exactly what you see in the picture (focus on one or two main points: the main character, a man or a girl, a landscape, a pet or a cell phone)
- Do not ignore the background. Show the details: colour, light, books, tools
- Give your personal impression. Be subjective.
To sum up:
The real thing
Use rich vocabulary (do not repeat words or expressions, if possible)
When you speak try to be clear enough to be understood by anyone
Take care of intonation (you do not ask a question the same way you describe a picture)
Speak good English