Ok, im not the best at this, but I decided to atleast give some pointers. First of all the body is very disproportionate, the hands are way too short, the stomach is area is too long, and the head seems too small. The leg position you got there is also not cross-legged, but more like just sitting on the floor and soles touching each other. I think you should work from reference, that way it would be easier to convey the right forms and position. You can also find tons of references to how the legs look in a cross legged position. You should definitely check those out.
Anyways, you should try making the arms longer, the body a bit shorter, and the head larger like in this little edit I made. I didn't change much just the main things that bothered me. It's not very good, but should atleast give you some pointers on how to continue. As for the colours and lightning you'd have to wait for some more experienced artists to help with those as they could probably do it better than me.