ACT NOW - In all cases something needs to be done quickly. I can't emphasize that enough. DO NOT WAIT, do something immediately. It can take 20 days or much longer (depending on the court's schedule) to get the first court date. Should the other parent refuse to allow any contact that can be a rather long time to wait.
NO EXCUSES - I have heard many excuses, such as "I'm letting my ex cool down", or "My daughter does not want to see me right now." These excuses may prevent you from the only actions that will allow you to see your children. In addition if you prefer an agreement, an agreement can still be reached after you have filed a court action.
ABSENCE MAKES OWN BARRIER - In my experience separation can become its own barrier in many ways, such as the children getting their image of the absent parent painted by the present parent or present parent's family. Typically the negative images wear off with constant exposure to the absent parent so they know that he/she is not bad. In addition a child may not want to see the absent parent because they feel that the absent parent does not want to see them, or that the absent parent does not know how to care for them. In many cases the longer it takes the less comfortable the child is with seeing the absent parent. Not only does the child think "why doesn't dad/mom want to see me," but judges question why a parent would let so much time pass.
ENFORCEMENT - In general if you have a specific custody order or decree of divorce you can call your local sheriff to enforce it. If your custody or or decree of divorce says something like, "By agreement of the parties" then the sheriffs usually won't enforce it and tell you to see an attorney. In most cases you should be able to see your children even if you owe child support. It is advisable that you speak to an attorney before you call the sheriffs office to enforce the custody order.
MODIFICATION - If your custody order or decree of divorce is old and doesn't reflect reality or if for some reason you are not happy with the amount of time or specific time ordered to you, you should see an attorney immediately. Delay can only hurt you! Make sure that you consult legal counsel before agreeing to a modification as you might be entitled to far more time with your children then the other parent is willing to offer you, even after not seeing them for a while.
CONSULTATION - My office offers a $100 consultation wherein we can get you a plan towards reunification with your child as soon as possible. Within the first consultation if you bring your prior orders (if any) we should be able to have a gauge of your possibility for success, a chronological detail of what court dates and paperwork is necessary, and an idea of what the matter will cost you.