Here's some of the thing I have learned so far –
When telling the story from a particular character's POV ask what would he think of characters as they are introduced and remember what they think of others also reflects his or her own life experience.
For example - a 40-year-old teacher at a school disco may think the girls have turned up in their underwear and not their best party gear. Well, when he was younger girls wore more clothes, or at least that was his recollection of things.
Giving characters a theme tune that makes you think of them when you hear it can work wonders. For instance an elderly woman who dreams of going windsurfing could have Young At Heart. A man who thinks he's god's gift to women could have You're So Vain. You play the song or hear it in your head and hey presto they're there in the room with you.
Speech tags he said and she said, may seem repetitive, but when you're reading they fade away and it’s almost like you don't see them. If you try and vary tags and write things like 'she said angrily,' 'he said brightly' that does start to grate with the reader. So minimise the use of these if possible.
When someone is speaking break up the dialogue with A and B.
A is for action i.e. 'She stopped speaking to brush the hair from her eyes, and then she inspected her chipped nail polish like she'd find the answer there.'
B is for body language. What are her lips, mouth, hands, shoulders doing? Is she sitting up straight or is she slumped? Are the feet still, shuffling, tapping, moving, shoeless (she's so relaxed she's kicked off her shoes).
It can be distracting to write when Elvis is in the next garden. Yes really. I live next to a pub beer garden and the impersonator is currently belting out Love Me Tender.