Glass Aid

1. Protect The Chip If the area is dry, cover the the chip on the outside of the windshield with clear tape.  This will seal out moisture and dirt until a permanent repair can be made. Bullseye and combination chips contaminate easily.
2. Try not to use the defroster; however if needed, use the lowest setting that will work to clear the windshield. Critical on crack, star and combination windshield chip damage.
3. Park in the shade, if possible, or leave the side windows down slightly to avoid heat building up in the auto or truck.
4. Don't use anything liquid to seal off the chip, such as nail polish or glue.  Doing this can render the chip nonrepairable.
5. Don't wash the vehicle; pressure from power washers or your hand and/or the temperature difference between the glass and water during the car wash may cause the chip to crack out.  Further any liquid getting into the break can contaminate the chip which can affect the appearance.
6. Don't apply windshield treatments like RainX or Aquapel, until the chip has been repaired.
7. Don't use sun shades, the type that unfold and are placed on the inside against the windshield. These cause the windshield to heat up and can crack your windshield. Particularly stars, small cracks and combination chips.
8. Don't slam the doors, trunk, or hood.  Avoid any other vibration to the vehicle. 

These tips may reduce the chance of your windshield cracking, however only a permanent repair will totally prevent cracking.