Originally Posted by Lazybones
Good things to keep in mind. Dialogue is one of those tricky beasts where what works in an actual conversation doesn't actually work on a written page. The hard part is using the tricks of writing to make the latter seem like the former.
I agree with this, sometimes if you make it too realistic, the dialogue actually becomes less realistic or "try-hard", it can also appear messy and difficult for the reader to read.
I think Irvine Welsh is the master of writing dialogue, he uses Scottish phonetics, but once you get it, it is like you are having a conversation in a pub with someone.
I write in first person and use a lot of slang. I use some phonetics. Instead of using he said, she said I usually cut from one sentence to the next.