You can store coriander leaves in the 2 most effective ways throughout the month. Like store coriander leaves fresh in a glass of water and zip lock bag. Apart from that store them as dry coriander leaves. Try any of the below techniques you like.

Remove Yellow and Wilted leaves: The first step to storing coriander leaves fresh for longer is to remove any yellow and wilted leaves from the bunch of the coriander leaves.

Rinse and dry the leaves: Thoroughly rinse the coriander leaves under cold water and remove any dirt or debris from them. After that pat dries with a paper towel. Make sure the leaves are completely dry before storing them.

Wrap in a damp paper towel: Now in a damp paper towel wrap the coriander leaves. This helps to keep the leaves moist and fresh. 

Store in the refrigerator:  In a zip-lock bag place the wrapped coriander leaves. Then keep the bag in the refrigerator for up to a week. Make sure to check the leaves every few days and replace the paper towel if it becomes dry.

Store in a glass of water: You can also fill a sturdy glass jar with cool water. Then keep the coriander leaves inside the glass, make sure all the stem ends are submerged but the leaves should stay above the surface of the water. Remember to change the water every alternative day to prevent bacteria growth.

Clean and Pat dry: At first cut the ends of the coriander stems to remove any damaged or wilted leaves. Clean the fresh coriander leaves to remove dirt or debris from them. Then pat dry the leaves with a clean paper towel to remove excess moisture.

Place Leaves in a Larger area: Now spread the coriander leaves in a single layer on a clean, well-ventilated area, especially a dry surface like a baking sheet or a mesh drying rack. Depending upon humid levels it takes a few hours to several days to completely dry leaves.

Store dry leaves: When the coriander leaves become completely dry and crispy store them in an airtight container or a plastic ziplock bag.