Here's a great tutorial from Rob Appell (Man Sewing) on basting:
https://www.youtube.com/watch?v=g-SC63erclc
He is working on a mini quilt, but the idea should be the same for QAYG. As a side note: he talks about ironing the sandwich to "secure" the layers together. That generally only works if you are working with natural fibers and a hot iron. With poly batting, you cannot get the iron as hot, so there's generally not much point in ironing the sandwich (you also need to be conscious of how many times you are applying the iron to your fusible if you didn't window it; windowing -- cutting the center out and just leaving 1/2" around the edge of applique -- will allow the center to remain unfused; if you left the center in, all that heat can dry out the fusible, typically in an uneven pattern resulting in some of the fabric pulling away from the background & weakening the fabric, potentially even creating tiny bubbles or waves in the applique fabric). I would only iron the individual pieces -- and make sure if you do need to iron the poly batting due to fold lines, that you iron only on the poly setting (learned that one the hard way!
).
Note that he does NOT tape diagonally on the corners or pull at them. Taping the corners creates dog ears. Pulling the quilt any tighter than 'just barely smooth' will create puckers on the back.
Hope that helps. Happy quilting!