You only want what's best for your hair. That's probably what prompted you to get hair extensions, too - to give your hair that extra length and volume and, not to mention, that it saves you a lot of time getting ready in the morning. However, getting the best hair extensions would also mean that you need to care for it in the best way to maintain its beautiful and fresh look.
Washing
Washing is the first and most important process in caring for your Brazilian hair weave, since this is not directly attached to your scalp, and thus cannot get the necessary nutrients. Before washing, your hair need to be free of tangles. Use a brush to carefully and gently comb from the bottom, making your way to the top slowly. Use a mild shampoo in washing every week or so, more frequently if you have been exposed to dust or engaged in activities that caused you to sweat a lot.
Conditioning
A small amount of conditioner should suffice in coating the weave and your natural hair. It should also go without saying that the conditioner should be rinsed well. Alternatively, one could use a leave-on conditioner. Applying oils to the weave will weigh it down and might even cause matting; avoid using it except when it loses shine. Preferably, you should use argan oil, but keep it to a minimum.
Styling
Gently brush the tangles out of your hair, supporting it where it is attached. Use a wide tooth brush or a detangling brush while only brushing a small portion at a time. It is recommended for the weave to dry naturally-that means no towel drying. Like natural hair, heat can cause the weave to be dry. If you absolutely must use heated tools, set them to the lowest setting possible. If your weave is braided or worn in locks, allow more time for it to dry and regularly spray on some anti-bacterial weave spray to kill the bacteria and any unpleasant smell.
Sleeping
Never go to bed while your hair is wet as this will cause tangles. Before going to bed, it is advisable to wrap your hair with a satin scarf and put it up. Do not tie it too tightly; this is bad for the weave. The pillow you use should also be covered with a satin cap or pillowcase.
 (Source: Five Ways to Keep Your Weave Fresh, Clutch Magazine)
