what are your techniques for getting that part from the plans to the actual wood? Do you trace the part from the plans onto paper then glue the paper onto balsa then cut that piece out?

If you don't mind destroying the plans, you can cut the part out and paste it on the wood.  An alternative method I use sometimes is to place the plans over the wood and prick holes through with a straight pin--then "connect the dots" on the wood.  Preserves the plan sheet, you can even Xerox it later and the pinpricks don't show.  Do this using 1/32" plywood and you have a template you can cut around for multiple parts (ribs, etc.).

--Ray

I use tracing paper from the art store.

Trace over the piece with a pencil. To transfer the drawing, flip the paper over, draw along the lines with a pencil, then flip the paper over onto your work. When you trace the part again, the pencil lead is transferred and your drawing is on the wood.

You do not have to destroy your plans; the tracing paper is also not destroyed and can be used many, many times. 

Ron

Ran out of Carbon Paper.  Went to an Office Supply store to get more and suffered "Sticker Shock".  $12.95 for 100 sheets!
 
Suggestion, do not try to trace free hand when copying parts.  Use "French Curves or straight edges" to get more accurate tracings.

Clancy

Carbon paper and then prick through with a pin. The dots show up better.

I use my scanner on most smaller stuff and then 3M 77 to the wood and cut it out . go asy on the 3M and it peels nicely when done.

I use double sided tape that's used for picture mats. It comes in fairly large rolls. I also use it to hold stacks of Ribs and other multiple parts to be cut. It just rolls off by rubbing a finger on it and leaves no residue.

I'm with Sparky on this.
Tom Morris sells a product called SeeTemp, short for See-through Template.  It's a sheet of red translucent plastic you lay right on the original plan and score with an Exacto Knife.  Snap out the shape and you then have a permanent template that you can use over and over.  Unlike paper it has rigidity similar to a plastic coffee can lid and will last forever.

I found mine at my local Hobby/Art Supply shop.  Any good art supply place should carry it. 
I just walked up to the counter and asked if they carry SeeTemp and they knew exactly what I was talking about. 

Howard Rush reported once that you could lay the plans on the balsa/plywood and just iron over it. A bit of the ink/toner transfers onto the wood. I haven't tried it, but it's about the only method I haven't tried.

I tend to make rib templates from plywood or aluminum, and other stuff from thin posterboard. Office Depot should have it.  I would probably try using Howard's ironing method, but iron onto posterboard, to make templates. Something like a profile fuselage isn't even worth making a template. Just lay it out with a scale and fine ballpoint pen, or build the core on the plans, and then sheet both sides.  Trim away everything that doesn't look right...   Steve