A good book is a personal gift that makes a statement to the child and that the family can pass down through generations. The message you write not only shapes a child's perception of the book, but is also a way in which your voice, ideas and feelings can be carried with them into the future. Always include your name, the date you give the gift and the reason for the gift.
If you are giving a book that was a personal favourite when you were a child, write a message telling them how old you were when you read it, who gave it to you and why you loved it, to create a link between your childhood and theirs. If you have a favourite passage or scene make a note of the page and paragraph in which it appears and say why you like it.
If the book contains a character or events you think the child can relate to, highlight this in your message. Focus on the positive nature of the characters outcomes of an event, such as: "I chose this for you because this (character or scene) reminded me of you and how well you deal with certain situations." Find a quote or sentence in the book and copy that under your message with the page number where it appears.
If you are giving an old family book, such as a Bible, write a list naming everyone who owned the book before the child, their dates of birth (and death if appropriate) and their relationship to the child. Describe the history of why it was first given and the occasions on which it has been passed on.
For antique books, consider writing on a piece of paper and sticking in the book with specialist antique tape, so you do not reduce the book's value by writing on it.
Poetry, Quotes and Sayings
Authors often start a book with a relevant quote or poem. Write your own short verse referring to the child, yourself and the reason for the gift. If you and the child have a shared favourite catchphrase that is relevant to the book, write that in. If you are trying to inspire a child to read more, look up sayings about books or reading on an Internet "famous quotes" site and write one of those.