The pins should be about 4 inches apart. I used the width of my palm and placed them away from seams (just easier that way). Start in the center and work your way to the edges, smoothing as you go. I place a small marble under the back to help with sticking the pins through. It raises the sandwich just enough you won't scratch your floor or pin to your carpet (yup, done that more than once). You can also use a grapefruit spoon to help close the pins and save your fingers.
If you will send me your address I can send you plenty. My hubby got me a frame and mid-arm and I no longer pin much. I would be happy to send you enough for a small quilt.