start with PRACTICE! purchase some inexpensive muslins, batting you like- make sandwiches, thread your machine with a bright, stand out color & practice! the practice quilts sometimes turn out fabulous! if not- they can be finished up & donated to the humane society---or a few of mine i gave to the granddaughters- they used fabric markers & painted on them after i had quilted them- they are their favorite picnic quilts...
lots of practice!
the lqs may offer beginner classes- and there are TONS of videos & tutorials on line- check out u-tube along with craftsy, ... if you search for machine quilting tutorials you will find links to literally thousands