Sometimes I will replace the raised panel lines by applying masking tape to either side of the panel line and smearing a bit of filler in the gap, just as thick as the masking tape. Seems to work well enough that once painted you wouldn’t know the difference. As far as scribing, I have a scribe, although I’m not very good at it.
Prime or not to prime. You’ll get a lot of differences on that one. If I’m using enamel, I usually won’t prime first, however if my final coat is acrylic, I will prime with enamel to give the acrylic something to grip to. I’ll do this especially if I’m going to do a lot of masking. If your painting gloss white or gloss yellow, priming is a must so the gloss goes on well. These I will usually prime with flat white.
Pin washing? Check out this link.
http://cs.finescale.com/fsm/modeling_subjects/f/3/t/128467.aspx