Show, don't tell. I say this a lot for the first two chapters when I do a critique :) Why? Telling is what we do naturally. ‘He did this and then he did that.’ (If you find yourself using a lot of adverbs, words that end in '-ly' and describe an action, you're probably telling.) It comes across as words on a page, and we don’t want that distance between the reader and your world. You want to suck the reader in to the story, make her or him forget the real world, experience your world through the experiences of your Point-of-View (POV) character.
Stop and think about the situation the character is in. What is he/she seeing? feeling? hearing? tasting? smelling? You don't have to hit every sense every time. Focus on sight (where appropriate) and occasionally season with something from the other senses.
When we walk into a room (or your character does) give us three details of the room. Same for new characters – what do they look like? But don't just say something like 'he was tall and had brown eyes and black hair (and definitely don't say 'tall, dark and handsome - that is cliché and makes for a weak sentence. The rule is: if you've heard/read it before, find another way of saying it). Make the descriptions part of the action. Tell about his height in relation to something nearby (does he loom over his opponent? does he duck when walking through a doorway? Tell us the length and color of his hair as something interacts with it. Does the wind blow it around? Does his opponent get a grip on it? Same for the eyes. Maybe do a 2-fer and have him impatiently toss his head to clear ink strands of stray hair from his earthy brown eyes. You get the idea.
It takes time and practice. Telling is much easier, and what we tend to do. Showing is something you have to work in during the editing process, and is something you have to think specifically about, fitting yourself into the scene and imagining what you would be experiencing. And yes, I still have this problem. Don’t hesitate to prompt 'show, don't tell' in doing a critique for me :)
