So far I only have one finishing detail but it's a neat trick. Personally I'm a fan of paintings being hung without a frame. You spend all this time on the composition, painting, colors and then the piece is wrapped in a frame that overwhelms everything you have worked for. Who knows, people might even notice the frame more than the painting.
This trick works great for pre-stretched canvases and especially well for gallery wrapped canvases. Gallery wrapped is a canvas that has a decent depth of over 1.5 inches and the staples are hidden giving the canvas a clean edge. If you have staples on the edges of your canvas just paint over them, nobody will notice.
Simply flip your canvas on its side. Look at the edge and notice the last colors used before the edge of the canvas. Now take your pencil and draw straight lines down the edge of your canvas separating each color.
Pretty simple right? Next, do the same thing for all for sides of your painting and fill in the color.
Now that's what I call a painting! Isn't it much nicer to have the edges painted as opposed to some sloppy white space. Plus it can now be hung by itself without a frame and viewed at any angle.