...without seeing the artwork in question or a screenshot of your situation can be tricky to say do this or do that...
...live trace has many settings to experiment with, and results can also be dependent on the quality of the image you are tracing...
...creating your own shapes would be by way of the pen tool in most cases...
...it is possible to smooth out vector lines using the smooth tool which is found within the pencil tool area (click and hold on the pencil tool to reveal other tools)...
...you can also adjust paths using the pencil tool itself by clicking and dragging over or close to an existing path...
...using the direct select tool (white arrow) or the convert anchor point tool (shift + C) is also another way to adjust curves, by clicking on an anchor point and adjusting the handles...
andrew
