Chris, not much to add to the previous advice. I use a large embossing stylus for this type of part shaping...one with a ball tip at least 1/8 inch diameter. You can get this tool at leather-working shops, like Tandy, or the scrapbooking section of crafts shops such as Michaels, Robers, Ben Franklin's, etc. As a tip, place the part you are shaping onto a firm, but yielding, surface. I use my mouse pad....it seems to have the perfect texture for a backing when doing the embossing. I recommend keeping with cardstock rather than bond paper. When joining parts, just use a simple butt joint without a joining strip or tabs. Just make sure the joining edges fit snugly together without any visible gap before applying the glue. I use brushed-on, thin-formula super glue. Hold the seam edges together before you add the glue....you might have best results by applying the glue to the end of the seam and let capillary action wick the glue into the seam. If I have difficulty keeping the seam together long enough to put on the superglue, I will use a bit of Aleenes Tacky Glue and hold the seam together long enough for the glue to start to set, then apply the super-glue. The white glue and super glue seems to work together to make one hell of a bond....however, it has been my experience that the exposure to the white glue residual produces a glob of gelled superglue on the brush tip, and the unused glue in the bottle thickens up and gells faster than exposure just to the moisture in the air. I use this gluing technique for nearly all joins on small parts and for the seams on cylinders (like gun barrels).
As another tip, since this technique tends to parts to fingers.....when removing the glued-on part, gently twist it off rather than pulling it off. When you glue youself to larger parts, you can minimize damage (to the part, of course....skin grows back) by rolling (twirling, actually) a thin dowel (like a bamboo poultry skewer) between the skin and the part.