You could buy a device which looks like a plain A4 size sheet of glass which is attached to a narrow base which enables it to stand unsupported. You then place a picture which you wish to draw flat on the table, on the right hand side of the glass, then on the left side (also flat on the table), place a sheet of watercolour paper. Both papers should be close up to the glass stand. The two papers are then horizontal on the table with the glass stand vertical between them. I don't know how it works, but the picture on the right, it then reflected on to the watercolour paper, and you can draw round the outline and features. Having done this, you can then paint your picture. These devices are obtainable in Art Shops and some Craft Shops. Good luck, and the more you practice, the better you will become.