[BillySan]

I taught an architectural drawing class at ASU when I went to grad school there. This is a common problem with a lot of drawings.

You might want to adjust the contrast of your scan. You can do this in PhotoShop (I think getpaint.net is a free option, though I've never used it myself).

As far as the actual drawing itself, you can go over it with a darker pencil. This will make the drawing "pop" or stand out more and it make it look so much better.

Going over it with pen on tracing paper is a good option too, but tracing paper is usually pretty flimsy and can rip easily. If you want to keep your tracing, I'd suggest a sturdier paper like vellum.

You could also use a light box to trace through to some thicker paper. If you don't have a light box, just tape the original and the new sheet of paper to a window and use natural daylight to trace through the paper.

Hope this helps.