What's the secret? Before they write, you absolutely MUST let them TALK!
Very few kids (or adults) like to revise or edit. When they write their first draft, it is usually the best they know to do at the time. Because of that, we don't ever use the term "sloppy copy"!
If there was something you as the teacher could do to improve that first draft, would you want to do it? I'm telling you. Let them TALK before the write!!!
One of my favorite ways to do this is with Inside-Outside Circles. I split my class into two groups. Sometimes those groups are random but usually I secretly group them according to language level or writing ability to make it even more productive. Half of the students make the inside circle (facing outwards) and the other half form an outside circle facing an inside circle partner.
I stand in the very middle of the circle (mushpot anyone?) so I can easily listen in on the different conversations. The inside partner shares what he/she is going to write about (a verbal rough draft). The outside circle partner listens as an active listener so he/she can TAG at the end.
After about 2-3 minutes of sharing and TAGging, I call for partners to switch roles and repeat the process. Then (this is VERY IMPORTANT), I have the outside circle move clockwise so that everyone has a new partner. Each student needs at least a second or third opportunity to verbally revise their draft. Some may need to abandon their first idea and try out a new one. They also need the chance to interact with different partners that will provide examples of quality drafts as well as constructive feedback.
Once students have shared their writing with at least 2-3 other partners, I send them to their tables to begin writing. It is amazing the difference that talking makes! Their juices are just flowing! You know those students that are typically slow-starters when it comes to writing? They get up to sharpen their pencils, they go to the restroom, they try to distract other students. Why? They don't know what they want to say! But, if they have talked and listened to others' ideas, they are so much more likely to get right to work.
I have tried this with students in grades Kindergarten through sixth grade and with adults. The time that you invest in talking will pay off dividends in higher quality writing.
Okay, so my secret is out or maybe you already knew. Have you tried talking before writing? Did it make a difference with your students?