According to my library book, (and I'm just trying this myself) it's useful to compost grass clippings and newspaper together is. Grass clippings are very heavy in nitrogen content, where as newspapers are mostly carbon. Good compost requires a mixture of nitrogen and carbon, as will as some water. The trick is to shred the newspaper and then pour water on it (damp, not sodden). Cardboard is good too. I've just started composting corrugated cardboard and egg boxes.
So, if you want to compost your grass clippings but find that they just turn into a slimy mess, try mixing them with shredded newspaper. (and you really do need to mix it all up for decent results)
Let me know how it goes. My compost is racing away; it may be the newspaper or it may be occasional feed of urine (which is also high in nitrogen)
Tea bags and coffee grounds compost well (one lady on the allotments swears by tea bags)
Here's a handy link on what will
compost well from the kitchen and garden.