Writing Clinic: Basic Tips

Thought I'd share with you one of the latest messages I've had asking about writing. It came from one of my readers via facebook but I get asked similar things all the time so I hope my answer helps. Tell me what you think or add your suggestions in the comments...

I don't know whether to describe a character in one big paragraph or a bit here and a bit there as the chapter goes on. Also i just can't seem to change the scene.
I'm having lots of trouble bringing the child from school to hom...