Pay attention to good lighting

Having a solid light source is an essential part of taking any kind of photograph, and selfies are no different. If you try to take a selfie in a dimly lit room or one with harsh fluorescent lighting, it wont turn out the way you want it to. Natural light is the most flattering kind, so try to take your selfie near a window or outdoors. Keep these factors in mind when you shoot
Keep the sun or other light source in front of you, a bit above eye level, for the most flattering shot. The light will brighten and soften your features, rather than casting harsh shadows across your face. If its off to the side or behind you, your features could appear shadowy or distorted.
Consider using a thin curtain to diffuse sunlight or a single light source. It makes the light softer and more flattering. It will give the impression of smoother, softer facial lines so that your smile appears more attractive.
Natural light renders colors more faithfully than artificial light, but you can use artificial light to fill shadows. If you dont have the best lighting, most modern digital cameras have some automatic color correction to make up for it.
Dont use your flash if you can help it. Itll create a forehead glare, distort your appearance and possibly give your selfie the redeye effect.