Best beginner Machine quilting book ever...
https://www.amazon.com/Heirloom-Mach...4KS6SMHFZ45Z6H
You can get it used on Amazon for basically the price of shipping. Well worth having in any library.
I also agree with Prism that straight line quilting with a walking foot is also a great way to get started and relatively easy. I used to do a lot of it and it is amazing how good an all over cross hatch can look. I also like to echo quilt seam lines and used the edge of the walking foot as a guide, lining it up with the seam so the stitched line ends up being 1/4" or 1/8" away from the seam. I found it much easier than SITD.
That said, there came a time when I realized I wasn't very good at sit down domestic machine quilting and to be quite frank, I didn't enjoy it at all. For my "fancy" quilts, I hand quilted. In 2010 I got a long arm and I haven't looked back since. I found that the way my brain works, frame quilting was much easier for me than moving the quilt under the machine needle.