Door lines and window frames

[awaken1973]

do you paint it after primer (but before body color)
or after whole body finished?

[Jay!]

In most cases, it's easier to paint the trim over the body color. How you do it is the tricky part. You can:
*Brush paint it
*Mask it off and spray it
*Use a paint marker or other permanent marker/pen
Masking looks the best, but it's hard and complicated to mask so many small, thin, oddly-shaped areas. Markers have the potential to be the easiest, until you slip. Painting by hand is in between, it's not easy, and it doesn't look fantastic, but it gets the job done.

As for panel lines, I love using a set of pens I have. They're made by Sakura, and I have a black one that has a tip .20mm wide. Otherwise, you'd have to thin down black paint, and run it through the cracks, then wipe it off the panel surfaces.