The important thing Denis mentioned is: 'contrasting paint'. I bought a portrait style 1900 for little money as the art merchant told me that there is no signature on the painting. Years later, dusting the painting I found a signature done by the back of the brush in wet paint that had the same color as the background... only visible by turning the canvas around until there is glare on the painting. The galerist would bite his nails.
I agree with Kingston , I think once you decide how your going to sign your art work, don't change use the same signature so it becomes recognizable IE; Kingston's signature.
I know an artist that writes his name so large that it becomes more important than the subject matter. Just don't over power your painting in proclaiming who did the work. I always try to place my initials in a place that doesn't distract from the painting. One time I placed my signature(initials) on a cow's hip as the brand. Another time I put it on the spine of a book. None of this means anything of note. You just have to figure out how you want to do it yourself.
Comments
None of the above. Use the back of your brush and sign into contrasting wet paint to expose the toned ground.
Denis