[Dark Evangel]

"-kun" also works well. It's mostly used for boys, but can also be used for students of either gender in schools, mostly by teachers (e.g. Takamichi calls Asuna "Asuna-kun").

Wikipedia explains it better:

Kun (君, Kun?) is an informal and intimate honorific primarily used towards males. (It is still used towards females, but rarely.) It is used by persons of senior status in addressing those of junior status, by males of roughly the same age and status when addressing each other, and by anyone in addressing male children. In business settings, women, particularly young women, may also be addressed as kun by older males of senior status. It is sometimes used towards male pets as well.

Schoolteachers typically address male students using kun, while female students are addressed as san or chan. The use of kun to address male children is similar to the use of san when addressing adults. In other words, not using kun would be considered rude in most situations, but, like the rule for using san in reference to family members, kun is traditionally not used when addressing or referring to one's own child (unless kun is part of a nickname: "Akira-kun"—Akkun)