I can sometimes achieve texture by using a textured fabric (velvet, burlap, laces, etc) or use a fabric that has a printed texture on it (trees, rocks, etc) but many times this is not possible.
Contrasting values in the quilt can sometimes create texture, the actual quilting on the fabric or even fabric manipulation can all contribute to the idea of texture.
Hand stitching adds texture both visually and by touch.
Fabric choices influence the visual aspect of texture by color choice and placement. Fabric structure - weave - is texture. Raw edges are fun to use, too. Paint and fusing also provide visual texture.
I love the feel of the texture on my pieces. My favorite method is to add embroidery stitches through the top and batting.
Couching yarns, ribbons, netting, and threads is also an effective surface design method that I enjoy using.
Beading is my most often used texture embellishment. Quilting with contrasting threads is also used in many of my pieces.