Years ago I checked out a video from the library by Jinny Beyer, who is well-known for her hand piecing. It's well worth checking your library to see if you can find her DVD. I think it's available on Amazon too, but really you need to watch it only once or twice. She does not mark her 1/4" seams, plus she has a very fast way of piecing that she demonstrates (basically moving the fabric onto the needle).
Some quilters use a small piece of tape on a fingernail that is marked with 1/4" from the edge. I think Tiger Tape is 1/4" wide; you could just snip off a small piece of that to put on a fingernail.
If you do mark, a mechanical pencil provides a more accurate line, and you would want to keep the marking light.