Don't add too much grass, otherwise you end up with a slimy mess (grass
takes a long time to breakdown)
Woodshavings are okay, again not in huge quantities. Things such as egg
shells, UNCOOKED waste, paper, newspaper...anything that will degrade over a
period of time.
Also, keep adding stuff regularly, and turn it over every now and again (it
needs heat to keep the bacteria going, so add'n of more stuff causes more
degrading, more heat gievn off, more bacteria produced to degrade more stuff
etc etc)
keep it damp (not soaking wet) and place an old blanket over an open heap to
keep it warm, or invest in a compost bin.
as winter arrives, the heap normally stops (or slows right down) due to temp
drop. keep adding stuff and it'll pick up during spring/summer. If need be,
add composter additive or manure to help it along.
Ours takes almost a year to rot down to useable stuff.

Hope this help

Stuart