Heres always worth a look;
http://www.teenhelp.org/forums/f112-...-ever-had-sex/
And as for tips, to be honest she may well have her own ideas about technique etc, take it slow, and go easy first of all, if something goes wrong shrug it off, practice makes perfect, just keep trying... Unless she wants to stop!
However its the most natural thing in the world, people have been doing it since well the first human...
Enjoy!
EDIT: For your first time though, you really want, time, space and somewhere comfy to be honest... leave stone floors and hanging upside down to later xD