There are many simple poojas and vrats one can observe during Naw Raatri, here are some.
The Naw Raatri Nariel Vrat.
Wrap a dried coconut in 1/2 yd of yellow cotton and tie the ends neatly in a "jura" at the top or stem end.
On your Pooja shelf, bedi or in your temple, place another piece of yellow cloth neatly as a covering (aasan) to fix a picture or murti of Maha Durga.
You can place the coconut in a tharia, and put it in front of the Murti. Using a lotaa, every day put a clean lotaa of water with tulsi, neeb leaves and flowers as an offering to Devi maa.
Using the Jaap malaa, use the mantras OM NAMAS CHANDIKAAYAI NAMAHA or OM DUM DURGAAYAI NAMAHA to do 108 chanting to Devi Mataa.
Use the Pakhaa Dhaar of 9 materials to offer at the Jhandi to Devi Maa, this can be done for the 9 days.