hi, i'm not an expert in chinese but just share some chinese rules for your reference:
1. chinese character actually can be read according to 部首 (radical ->
http://www.yellowbridge.com/chinese/radicals.php ). but sometimes got exceptional cases.
E.g.
Door (门) itself is a radical, pronounce as (men2)
We (我们) -> 们 is also pronounced as (men2)
Other radical such as申(shen1), the following all pronounce as (shen1) as it has the radical 申: 伸 (protude or give or to get), 审 (punishment), 呻(groan) , 绅 (gentlemen).
2. Each radical actually has certain meaning itself. e.g. 女(nv3) means female, thus when it combine with other radical, it always refers to female when talking about people, e.g. 妈妈,姐姐,她...
The other good examples are:
鱼 (yu2) means fish. When 鱼 is combine with other radical, it referring sea creatures e.g. 鲸(whale), 鳄(crocodile) and etc.
虫(chong2) means insects. When虫 is combine with other radical, it belongs to insect groups. E.g. 青蛙(frog), 蚊子(mosquito), 蜜蜂(bee)..
2. You can group same pronunciation but different character together to show to your kids: 心(heart) and 新(new).
3. sometimes Same characters has different meaning e.g. 长 has pronunciation: chang2 / zhang3. Chang2 means LONG, whereas zhang3 means ELDER.
4. The Chinese character actually evolved from drawing in ancient time. Thus, you can teach your child to draw to learn the Chinese character. E.g. shown in this website
http://www.zein.se/patrick/chinen9p.htmle.g. 林 (lin2) is actually referring to 2 trees.