Don't nag! Do you find yourself constantly asking in exasperation, "Have you done your homework yet?" Take yourself out of the nagging role by making a positive statement, such as, "You can go play with your friends (or watch your favorite TV show, have a root beer, and so on) after your homework is done."
To avoid battles, establish a routine in which homework is done at the same time each day.
From "Right-Brained Children in a Left-Brained World," by Jeffrey Freed and Laurie Parsons
When you help your child with homework, you may model "thinking out loud" or "self-talk" by verbalizing each logical step needed to solve a problem or to complete a task. The child not only learns that it is okay to talk to himself while working; he also learns a process, asking questions of what the next step is, and telling himself, "What I need to do next is... " Having such a dialogue appears to help the child who otherwise tends to rush through homework. The self-talk technique is especially useful in doing math problems and while writing.
From "Power Parenting for Children with ADD/ADHD," by Grad L. Flick, Ph.D.