Honestly, stitching in the ditch is probably not the thing to do if you have never quilted before. If you go off to one side or the other, it can be very noticeable.
A LA quilter taught me an easy way to do quilting that doesn't require precision and comes out really nice. She said to draw diagonal lines at 3" intervals and then sew a wavy line over each diagonal line. Draw diagonal lines going the other way and do more wavy stitches over that.
I drew some diagonal lines in black in the picture below to give you an idea of how it's done. Behind those black lines, you can see the wavy stitching. This is so incredibly easy and no one will ever know if you stayed exactly on the line!
And like the others have said, a walking foot is an absolute must.