Descriptive writing

Begin with ideas, not grammar. Grammar is only a tool.
Choose the words and structure to express your ideas.
You have power and control over your grammar and words, not the other way around.
Writing is a discovery and development process. Sometimes you have to write things down in order to "discover" what your ideas are. Then, by looking at your ideas on paper, you can see them from a different perspective, and this enables you to think about and develop those ideas even further.
For descriptive writing, take notes to identify your ideas.
Be specific. Write as many details as possible.
Use the five senses to discover what is/was going on around you.
What did you see, hear, touch, smell, or taste? (external factors)
Also, consider what is/was going on inside of you.
What are/were your thoughts, feelings, motivations? (internal factors)
What are/were your actions? (actions often manifest your thoughts and feelings)
Once you have written down detailed notes of internal and external factors, look carefully over your notes to decide which ones can be incorporated and used in your description.

You decide

Point of view
Dominant tense

• Simple present
• Simple past

Word choice
Order

• Chronological (time)
• Spatial (by location)
• Order of importance
• Other

 source : http://www.eslgold.com