Store your collection in a cool part of your home. If you can afford air conditioners and your collection justifies it, it would be a good thing to have. Sunlight is poison for paper. Whatever you do, keep your newspapers out of the sun. If you have any framed papers, be sure that the sun doesn't hit them at some time during the day.
Flourescent lighting is also harmful to paper.
Use incandescent lights for reading or displaying your papers. Store your papers in the dark if at all possible. Store your collection in a place that's cool, dark and dry. You will probably want to put some or all of your newspapers in holders to preserve them. However, after a year or two the poly will start to yellow and must be replaced.