If there is any basic accessory almost every photographer should own, it's a 5-in-1 reflector. Versatile, portable, and cheap, I have one in my bag at all times. This excellent video will show you the many different uses for a 5-in-1 reflector and how you can employ one to improve your shots.
Coming to you from Vanessa Joy with Adorama TV, this great video will show you the many different uses of a 5-in-1 reflector. 5-in-1 reflectors are incredibly versatile accessories, as they can be used to flag light to increase contrast, diffuse hard light to soften it, reflect it to fill in shadows, increase specular highlights, add warmth, and so much more. They do tend to get misused a bit, though (people tend to default to using only the silver side, which might not provide the result they're actually looking for), or they often position it improperly. Along with its versatility and price, that's why I believe a 5-in-1 reflector is one of the best tools a new photographer can use to learn how to shape light, and it will continue to be useful as you become more advanced. Check out the video above for the full rundown.