If I have to go to court to decide custody/access, how can I best prepare?

You can best prepare by firstly, hiring a lawyer.

It might also be beneficial to work out an arrangement with your former spouse/partner beforehand to present to the court. This can have the effect of reducing the time that you will need to spend in court as well as the cost.

If that proves to be impossible then you should gather evidence showing that granting custody to you and access to your former spouse/partner (or vice versa) would be in the best interests of the child. You should try to illustrate to the court that granting sole custody as well as physical custody to you (or your former spouse/partner) would be the least disruptive alternative for the child. You should also have a plan ready to present to the court, try to determine what it is you want in terms of custody or access to the child.

A good reference to follow when preparing for court and gathering evidence to support your case is s. 24 of the Children’s Law Reform Act. This section provides a complete list with many relevant considerations that if satisfied will usually determine what the best interests of the child are.

Merits of application for custody or access 24. (1) The merits of an application under this Part in respect of custody of or access to a child shall be determined on the basis of the best interests of the child, in accordance with subsections (2), (3) and (4).
Best interests of child (2) The court shall consider all the child’s needs and circumstances, including, (a) the love, affection and emotional ties between the child and, (i) each person entitled to or claiming custody of or access to the child, (ii) other members of the child’s family who reside with the child, and (iii) persons involved in the child’s care and upbringing; (b) the child’s views and preferences, if they can reasonably be ascertained; (c) the length of time the child has lived in a stable home environment; (d) the ability and willingness of each person applying for custody of the child to provide the child with guidance and education, the necessaries of life and any special needs of the child; (e) the plan proposed by each person applying for custody of or access to the child for the child’s care and upbringing; (f) the permanence and stability of the family unit with which it is proposed that the child will live; (g) the ability of each person applying for custody of or access to the child to act as a parent; and (h) the relationship by blood or through an adoption order between the child and each person who is a party to the application.
Past conduct (3) A person’s past conduct shall be considered only, (a) in accordance with subsection (4); or (b) if the court is satisfied that the conduct is otherwise relevant to the person’s ability to act as a parent.
Violence and abuse (4) In assessing a person’s ability to act as a parent, the court shall consider whether the person has at any time committed violence or abuse against, (a) his or her spouse; (b) a parent of the child to whom the application relates; (c) a member of the person’s household; or (d) any child.
Same (5) For the purposes of subsection (4), anything done in self-defence or to protect another person shall not be considered violence or abuse.