Because of the unique characteristics of the harp there are elements of the notation which are different, but essentially the harp is notated on two staves like the piano.
Occasionally you might like to add pedal markings to the score (in particular for glissandos) but normally the harpist will work out their own pedalling.
Harpists can only play four notes simultaneously in each hand, and 4 note chords must be close together as the streches become difficult.
You can mark which hand you want to play particular notes by marking m.d (main droite or right hand) or m.g (main gauche or left hand) but normally you can leave this for the harpist to work out.
Key changes and chromatic notes require planning by the harpist -if possible try to leave the harpist a little time to change pedals if you require lots of chromaticism or a complicated key-change.
Unless specified a harpist will assume that notes should be allowed to ring until they have to be stopped (e.g. to change pedals).
Certain effects characterise the harp's sound, and can be very effective. Glissandos work very well, as do arpeggios and repeated figures, but don't be afraid to give the harp a tune, as long as any other instruments have quiet dynamics so the harp can be heard.