Clip threads, front and back. Square the top and the back. The back should be at least 4 inches larger than the quilt top all the way around. If the top has been pieced to the edges or if the fabric tends to fray, stay stitch all the way around. Make sure seams are intact, not coming apart at the joinings. Definitely do a final pressing, not only will it make the quilter's job easier, it gives YOU a final check on undone seams, threads to be clipped, etc
But discuss it with the person who is actually doing the quilting, they may have other requirements.