I've just been told my child needs a hearing aid
If a child accepts a hearing aid
If a child does not accept putting on the aid
If a child rejects use of the hearing aid
I'm having problems keeping the hearing aid in my child's ear

I've just been told my child needs a hearing aid

Some children will accept use of the aid from the first day, while some will not accept the hearing aid without kicking, screaming and throwing a tantrum. Most children usually fall somewhere in between.
A child's interest or lack of interest in using a hearing aid will depend on a variety of factors including their residual hearing level, degree of benefit from a hearing aid, developmental stage, disposition, and ability to adjust to new things in his/her environment (new shoes, new hat, etc)
Below are a few strategies from the support group DeafHear that may be helpful in the journey of promoting a child's hearing aid acceptance and use.

If a child accepts a hearing aid

Encourage its use as much as possible during the day. If a child willingly keeps on the aid, there is no reason to remove it except for comfort purposes at night or nap time, when the child is swimming or bathing, or perhaps when the child is in a situation where he/she cannot be closely monitored for possible loss of the aid.
When the child is ready to remove his/her hearing aid, have the child participate in the process of putting it away.
Provide a clearly marked box for the aid to be placed for safekeeping. Place the box in an area where the child can learn to put it away independently.

If a child does not accept putting on the aid

You will need to stay as calm as possible and try and make it fun for the child to try the aid.
Try to introduce the aid in a variety of situations. If the child does not accept it at one time or place, they may accept it at another time or place.
If one family member is not successful in placing the aid on the child, have another family member try it.
Play games with the child having him/her put the hearing aid on an adult, doll, or stuffed animal.
Give the child an opportunity to look at and touch the aid. Place it on a table and let the child touch it and try to put it on himself/herself. (Then maybe he/she will let you help place it on them)

If a child rejects use of the hearing aid

It is up to the family to decide if, how, and when it is worth fighting the battle of getting the child to accept and keep the hearing aid on.
Try to determine if there is a reason the child may be rejecting the aid using some of the strategies described below.

To determine if the child is having trouble adjusting to the ear mould, introduce the ear mould alone. Have the child adjust to mould use alone. Having a mould in the ear for the first time is like wearing shoes for the first time. It is a new experience and something a child may have to adjust to.

Once the child adjusts to the mould, put the hearing aid in place, but leave it in the off position. Have the child get used to the weight/placement of the aid/mould together, without sound.

When the child seems to accept the aid/mould with the aid in the off position, turn the aid on and to the specified volume. If a problem now emerges, you may suspect that the rejection is related to the sound.

If it appears that the child is bothered by the sound, adjust the aid's volume to a level where the child appears tolerant. Use it at this level until the child has an opportunity to adjust to sound. When the child appears to accept use of the aid at a low volume, attempt to turn the aid to the recommended volume and observe if similar discomfort returns.

If a child demonstrates discomfort directly related to sound, keep the aid at the accepted lower volume and contact the child's audiologist. This will provide helpful diagnostic information to the audiologist in the continuing process of determining your child's specific hearing levels and correctly fitting your child's hearing aid. The hearing aid may need further internal adjustments that can only be made by the audiologist.

I'm having problems keeping the hearing aid in my child's ear

String style eyeglass holders can be attached to the hearing aid, and pinned to the child's shirt. If the aid falls off, it will stay with the child.
A fashionable fabric hairband can be used to hold the hearing aid in place.
Toupee tape (for hairpieces) or other double-sided tape (with mild adhesive) can be used to attach the hearing aid behind the child's ear.
The hearing aid tone hook (plastic half moon shaped piece that attaches to the ear mould and the hearing aid) may need to be modified by the child's audiologist to a position that best hugs the child's ear.
The tubing on the ear mould may need to be cut to a length appropriate to best keep the aid in place. If the tube is too short or too long, it may cause an inappropriate fit and discomfort for the child.

'Huggies' are a brand name device that help keep hearing aids in place on a child's ear. These circular plastic hearing aid attachments come in a variety of sizes and must be measured specific to a child's ear. Huggies can be ordered via most hearing aid suppliers. Ask your child's audiologist about them, as they must be measured to fit each child.

"Otoclip" is a lightweight plastic cord and clip that attaches easily to the child and the hearing aid so the aid will not be lost if it comes off of the child's ear. These clips can also be ordered as "critterclips" with animal clips that attach to the child's clothing. These clips can be ordered through most hearing aid suppliers.