Plan Your Work
Think of this as a job. Plan your work, and then work your plan. Outline the steps you need to complete -- in order. Give yourself specific plans, organize those plans, and make sure you give yourself measureable and time-based goals for each.
Start Collecting Documents
Whether the documents you collect relate to financial history (bank statements, credit card statements, tax records, etc.) or artwork/school-work from your children, expect these things to slowly disappear once the divorce process begins. If you need to put a strong case forward, you'll need documents to backup your claims.
Meet With an Attorney for a Free Consultation
Most attorneys offer this service. While it'll be difficult to get actual legal advice, learn about the process before it begins, and do your homework in finding a lawyer with whom you can connect with and feel comfortable with.