Well, to begin with, character design is really hard. It requires a lot of knowledge of anatomy, gesture, costume design, etc. etc. So, the first thing a character designer does is thumbnail sketches to work out their ideas. I did a couple to show you how they should look. I suggest you start there, and then do some more finished drawings based on your thumbnails. I hope this helps :)

Hey, if you are trying to design characters with multiple sets of arms I suggest you have a peek at some Hindu deities. I think it will look aesthetically more pleasing if the lower set of arms connect higher up the torso closer to the upper set of arms, as if the shoulders are joint together and more in horizontal allignment. Other than that I can see some anatomical errors: the legs are too small, the head is too big and circle shaped and the torso doesn't taper enough towards the bottom. Other than that your off to a great start. Good luck. I didn't draw the attached images btw, it's just as example. Google image search for Hindu deities like Shiva etc..

I dont know anything about designing a character, but if you want to make a 4 armed humanoid torso i wouldnt spent too much time with anatomy. In reality it would have all the same parts that your arms have, so it would have another shouldergirdle, back muscles, penctoralis whatever. So I would either make the arms not "normal" or just make it look cool without too much tought in to anatomy. you could look for inspiration in animals/insects with multiple limbs. Also check characters like Goro from mortal kombat.