Put new wiper blades on them.

It depends on what's causing them. First of all, clean the rubber blades. Get a chux or paper towel and wipe all of the gunk off the blades. Clean your windscreen at the same time - use windex or glass cleaner to get all the gunk of there. Cleaning your windscreen regularly will prevent buildup of oil and other contaminants that are thrown up from the road or other vehicles around you. These contaminants will cause streaks. If that doesn't work, you may need new wiper blades. If the wiper blade is worn, it will not contact the glass properly and will leave streaks. The worst case scenario is that your windscreen may be scratched. There are two causes of this: either you've had a bit of sand/debris stuck to the wiper blade that has scratched a groove into the windscreen as the wipers have been used, or the wiper blades have worn down enough to let the metal frame behind them scrape along the glass. This will scratch a groove into the glass as well, and you'll find that the wiper blades won't pick up any water in that groove, which will leave a streak. If you want to be able to use your wipers less, keep your windscreen clean, and maybe use a product such as rain-off. It helps make your windscreen slippery, and the water will usually run off on its own, much easier than without rain-off. I tend to avoid home remedies such as using egg or potato.

Apply wax (the kind you use to polish your car) to the windshield. Of course new (or newer) wiper blades help as well, the wax helps the water that hits the windshield to repel better (just as it would on the paint).

This works for me. first, buy new wipers or wiper blades. second, i use 409 to completely clean my windshield, before using the new blades. third, i use zep professional glass cleaner....its at big lots and home depot. this one, two cleaning method is very effective. the 409 gets rid of road grime, grease and bird droppings. the zep clears away the residue left by the 409. it works for me. try it!!

Also, coca cola straight from the can, works in an emergency.

The best answer i know of was on the RAC tv commercial, they say rub vinegar on the blade

A mechanic at a car dealership told us to put some WD-40 on a paper towel, and run that part of the paper towel over the wiper blades. This will thoroughly clean the blade, and restore it to almost-new. This has saved us the cost of new wiperblades many times!

Put a little wood alcohol in the washer bottle, sometimes called methylated spirit, this will dispel grease and grime and leave your windshield sparkling