Not a bad start. Just a bit more practice with the simple forms and rotation of those forms. What makes a hand look believable is when the fingers overlap one another. I did not see that happening with your sketch. Also, be careful with the proportions of the thumb. You can always take photos of your hands or your friends for a strong reference. Sometimes it is very helpful when trying to tackles challenging perspective views. I pray this helps you along your artistic journey and keep practicing!