Hi, This is a common topic so you are not alone! The best solution is to practice a lot. If you have a tablet, draw with swift confident strokes and your line work will improve over time.
Some programs like SAI have automatic smoothing that will help smooth your lines but also reduce the precision of your details. vector programs like illustrator and inkscape (free) are also an option but everything has a learning curve!
Personally, I find that a canvas size of 2000 pixels or more is a good place to start. You can always reduce the size later and that may smooth out some of the smaller wobbles. I use the pencil tool for line art but some people use the brush tool.