Help Auto-Focus on d5000?

I just got a Nikon D5000 and I was taking shots outside with my friend and it wasn't focusing well and then a little later I did some random shots and it can barely focus. By focusing I mean clicking down half-way. I need it for tomorrow for a casual photo shoot.

Make sure the switch on the lens is moved to af setting and not mf.

Also, do your homework sport - read the manual.

By later did you mean you were shooting in very low light? AF works best with better lighting conditions. Try focusing in a brightly lit room.