I love the diamond quilting design!
Are you using a walking foot? If not, you may want to check it out. A walking foot can make the process of quilting a project go smoother on your sewing machine - less drag etc.
I really like your fabric choice and the diamond quilting pattern! Definitely stick with using a walking foot. I mainly do Quilt As You Go (QAYG) but do have to do stitching in the ditch to quilt down the panels so here are the tips I have received from fellow quilters. You may already know these tips, but here goes!
*When making your quilt “sandwich” (topper, batting, backing) lightly spray the back of your topper with something like 505 temporary basting spray. Then smooth a piece of batting slightly larger than the topper over that. Spray the batting and smooth the backing over the batting to create the sandwich. The reason you cut the batting and backing larger is that the stitching causes some shrinking of the fabrics so it helps compensate for some distortion. It also helps keep your piece as close to your desired finished size as possible.
* Flip it over and smooth it out really well (again!) Then using some curved quilter’s safety pins pin the three layers together. I was taught to use them liberally because they hold the pieces together to help ensure accurate quilting. Being curved, they are easier on your fingers as you open and close them.(You can get them on Amazon or any sewing/quilting shop.)So….I guess my estimate is about every 5-7 inches apart or so.
*When doing your stitching, work from the center outward to help prevent puckering. You should not have any unquilted area larger than your hand. I may fudge on that though myself. I think it depends on the piece and quilting design.
*Square up your piece and cut it so it is as close to the square or rectangular shape and size you originally want (I say it this way because sometimes this is my most challenging part and I am not always the most accurate at it ) I slice away incrementally to help me not go too crazy and wind up with a pot holder instead of a quilt
* I personally like a binding on my runners and quilts. I think it offers you an opportunity to choose another fabric to enhance the main piece, not to mention giving it a nice finished edge. If you are unsure about how to do a binding with mitered corners there are a lot of great videos on YouTube. Let me know if that interests you and I could post you some links. That is how I learned and truthfully, I enjoy putting on bindings now .
Quilting is an ongoing learning experience, but so very enjoyably IMO!