I try to incorporate mine into the piece so it does not clash or stick out but I generally keep the same mark no matter how it is applied. But my work mainly stays on the computer so it is easily integrated..
Are you asking what clever ways can you create your mark? That will come to you eventually and will evolve many times if you are like me.
It is your own choice. . I have tended to sign my paintings on the painted surface with my initials followed by the last two digits of the year in which they were painted. . When I feel that such a signature would detract from the composition, I sign on the reverse side. .
i sign everything in black