Decide what schedule will work for your personal life. As much as you'd like to work less, you may not be able to afford the pay cut that comes with part-time work. Make sure you understand whether your employer reduces benefits for people who work less than full time.
Also, look at your work style and child care realities. Working from home may sound great until you're trying to concentrate on a report with three screaming kids underfoot. It can also be isolating, especially for introverts who need the encouragement of close quarters to interact with their co-workers.
Investigate childcare options. If your children are still little, see what you would save by cutting back on child care. Some centers don't really discount part-time care, so you might want to continue full time to retain the flexibility at work. If you have a babysitter, gauge how open she would be to a more flexible schedule with possibly fewer hours.
Make sure you have a backup for personal responsibilities, such as the inevitable sick child. Have a frank discussion with the people in your life to get them on board, whether it's your husband, mother or school carpool buddy.