I am an unmarried father of two girls who wants full custody of his children due to neglect from their mother. How do I go about this

You need to document all her neglect days, times and anything and everything you can and go file for full custody. It depends how significant the Judge feels it is and he may possibly have Child Protective Services investigate.

Does she already have any court ordered custody papers?
Does she let you have visitations?
Do you pay child support?
Is anything an agreement just between you two or do you have any court orders of any of these? -custody/visitation/support?

Try to give us some more info on this so we can help better.

If the mother did something and you have proof then file papers with the court. I strongly say get an attorney in your area that does this kind of case, proof or not you will need one for this. It will most likely be an up hill battle.

If you only think that something is going on then call CPS and have them look into it. As much as I dislike them, they will open a case and look into it and if they find anything then they can take their letter (cause that is all they will give you) to court.

Like I said come back and give more details and we can help better.