Pushpins work better than any of the plastic painter's points from the hardware store (and the pushpins don't slip)
This is not some revolutionary thing, but it seems like every time someone sees me doing thing when I'm making picture frames i hear, "oh, why didn't I think of that?" I used to have all sorts of strips of wood cut to keep the frames off the table top (to prevent stain and finish that drips from the frames from making them stick to the table). The pushpin thing came to me when I was not working in my normal shop, therefore did not have anything to keep the frames off of the table top. I was ready to go to the hardware store to buy something that I normally make when I saw a few pushpin and thought, "why didn't I think of that sooner?"