This is not bad. The lighting is pretty good, if a little under (I know it's low key, but the highlights could do with a tiny nudge), and it could do with a hair-light to separate you from the background a bit more. You've also done well to control any reflections in the glasses, but my biggest issue is with the pose.
Your pose looks very tense and I can see it is all to do with your initial position relative to the camera which has led to a chain reaction of tension throughout your body. Here's how I see that chain reaction:
1. You are too side-on to the camera which means that:
2. your head is at too large an angle relative to your chest (almost 90°, by the looks of it), which means that:
3. as you've leant back, your head has gone with your back, but you don't have enough give in your neck to tilt it forward to balance your weight, which has caused that tense tendon to stick out of your neck, trying to hold your head upright and:
4. your arms being held in an un-natural position over your (tensed) stomach, which is your body's way of trying to counteract the weight and correct your centre of gravity.
I can even see your jaw is tense as your neck muscles strain to keep your head up and prevent you from toppling backward.
For leaning poses, put one leg in front of the other and "pop" the hip of your back leg - that provides a stable platform to place your weight on. Then, lean back allowing your spine to bend into an "S" shape (lower back curved in, upper back bowed out), but rotate your upper body around towards the camera so that your weight is mostly down the rear-most side of your body. Now that your body is rotated towards the camera, you can get your chin down and tilt your head slightly in the opposite direction to your lean and that will balance you. Your arms should then be free from balancing duties and you can fold them, hang them down, put them in your pockets or in your hair, whatever.
You'll find you can actually hold that pose for a while and your neck and jaw will be nice and supple for smile!
