A walking foot helps with straight-line machine quilting, and can even be used for gentle meandering curves or large half-circles.
For free motion quilting, you typically use a darning foot (and drop the feed dogs, or cover them if your machine doesn't have a drop option). The darning foot hops up and down with each stitch, allowing you to freely move the quilt sandwich around. Free motion quilting usually takes quite awhile to master, as it takes skill to achieve even stitches.
My favorite way of holding the quilt layers together is with spray basting. If you do a search on this forum, you should find several recent threads on this. Spray basting works best with cotton batting. 505 seems to be the favorite spray basting brand here, both for holding the layers securely and for lack of odor. Spray basting is basically repositionable glue that you spray between the layers to hold together -- sort of like a huge post-it note!
I like to heavily starch my backing fabric before layering. This helps stabilize the backing so I don't end up with puckers and tucks later. A search on "starch" or "starching" should turn up some recent threads on that topic too.
If you are new to machine quilting, I would recommend a cotton batting (I like the traditional 100% cotton Blue Ribbon batting, or an 80/20 batt). They are less slippery than polyester and thinner, which makes manipulating the sandwich under the presser foot easier. If you don't mind a slightly stiffer drape, Warm and Natural is an excellent cotton batting to use for machine quilting. Warm and Natural requires less quilting than other cotton batts (lines can be up to 6 or 7 inches apart, whereas traditional cotton is best at 2 or 3 inches max).
If you opt for a walking foot and feed dogs up, the easiest pattern would be straight or meandering lines that run from one end of the quilt to the other. You do not want to have to turn a queen size quilt around under the presser foot!
Meandering would be a very easy and casual pattern to do. I don't know how to describe it, except you would start at one end and gently curve one way and then another as you sew down the quilt. Succeeding lines could echo the first one, or you could allow yourself to meander in different directions and intersect previous lines. You could turn the quilt sideways and make meandering crosshatching lines too, so you have lines going both top-to-bottom and side-to-side.
The walking foot with feed dogs up would ensure that your stitchese are smooth and even. Be sure to create a test sandwich first to practice on. Usually you want to lengthen your stitch somewhat to allow for the thickness of the quilt.