How do I get primary custody of my son?

There is not a mathematical formula for getting custody in Texas.  Instead, the courts use a standard called the "best interest of the child," to decide who should get primary custody of a child.  The family code and the appellate courts list things that the court can and will take into consideration when deciding who she be names as the managing conservator of the child.  These factors include:  the parenting abilities of each parent, living conditions available with each parent, the resources of each parent, preference of the child, and any special needs of the child(ren).  The courts will also look to see who has historically been the caregiver of the child and will review any allegations of abuse or neglect.  No one factor controls.  The court will look at the "pros and cons" of appointing each parent, and make a decision that they think will be in the best interest of the child.

That being said, there are things that a parent can do to improve their chances for obtaining custody.  Having an idea and a plan before asking for custody always helps.  Have a room ready for the child to live in.  Know which school they will go to school and any special advantages of the child attending the school.  Have a family doctor (and dentist if possible) lined up for annual check-ups and shots.  Know what other educational/recreational resources are avaible in your area.  This could include a park, a zoo, libraries, museums, local theatres, or soccer programs.  There is not one perfect "program," but the general idea is to show the judge that you've thought about what it takes to be a good parent, you have taken steps to be that good parent, and you are able to follow-through on your parenting plan to be the best, daily resource for the child.