Print out a long form financial affidavit and fill everything out as detailed as possible. You can find this form here: http://www.flcourts.org/gen_public/family/forms_rules/902c.pdf. Gather three months' worth of paystubs, bank statements, and three years of income tax returns. Also gather together copies of deeds, auto titles, related to ownership of assets.
You will also have to do the same for your marital liabilities, so get all your credit card statements, mortgage loan statements, bills in general, so that you have an idea of what expenses lay ahead. Sometimes during divorce, it's harder to get the other spouse to cooperate in paying the joint bills so you may have to really pinch your pennies through the process until a final determination has been made on how these expenses will be remedied after the divorce.
Familiarize yourself with your children's on-going monthly expenses.
Itemize monthly on-going children's expenses so that you are comfortable and are able to say that this is how much is being spent on the children as far as health insurance, after care, day care, tuition, etc. The more comfortable you are the more believable you will appear should you have to testify in court regarding these expenses as the judge makes a ruling on child support.
Attempt amicable discussion with your spouse if that's possible to avoid excessive attorneys fees.
If you and are your spouse are amicable, try to see if you can resolve all of the issues relating to custody, alimony (if applicable), child support, and marital property distribution. If the two of you are able to resolve this together, that means more money in your pocket to spend with your children versus spending on pricey litigation and court costs.
Consult with your pension plan and/or retirement plan administrator to determine what needs to be done once you've filed for divorce.
Before filing for divorce, you should contact your pension plan/retirement plan administrator to find out what you can do to ease the transition from married to divorce as it would affect your retirement/pension plan. Ask for the forms in advance and also ask them for most recent balance information as well as a detailed history so you know what kind of monies are involved.
Maintain the peace at home. You are captain of your ship.
Remember that divorce is a very trying time for families. As a parent, your children will look to you for emotional support. Try to understand what they're going through and make sure it's clear that it's not their fault you are going through the divorce. Never discuss specifics of the divorce with your children, especially no badmouthing of the other spouse. If you can manage to steer your ship to safety, you will be all the more relieved in this process. Divorce is one of those things that highly depend on the parties involved. You get to decide how long it goes and how expensive and painful or painless it can be.