I am still surprised by how much I have yet to learn - and I have been "around" sewing for over 70 years.
Some people practice "steering/manipulating" the machine by using an unthreaded machine and paper - one can use lines or drawings - and one can see by where the needle punched holes in the paper how well one did!
A caution - this may tend to dull your needle - but - this is for practice. You can use junk mail, whatever.