How should I draw body parts and use them as smooth joint ?

[tolgad17021711]

Hİ I'm new on Digital Animation, How can I make that smooth ? I need to fill the spaces. Is it possible ?

[vincents38754426]

Make the joints end circularly, with both joints being equal circles or very slightly different. Be sure to but the bone point in the center of the two circles so they pivot around each other.

tl;dr  Make the joints circular instead of flat.

Hope this helps.