All the senses can be utilised to create an impression. Think about what you can see, hear, smell, feel and taste.
Even when describing an entirely fictional setting or type of character, such as an alien or fantasy monster, you need to base your description on recognisable terms.
Consider how the senses are used to describe this scene.
He walked into the classroom and crossed to his desk. The floor was worn where years of boys had kicked and scuffed in their rush to escape. A damp, sickly-sweet aroma arose from the pile of jackets crushed in one corner and a blind tap, tapped against the window where a stone or ball had cracked the glass. Mr Jones rubbed his hands across the smooth polished top and examined his finger tips for dust.