Are you looking to make your own castings? In what material?
I'm not a pattern maker per se, but I have some experience with casting zinc in permanent molds, and I've messed some with patterns for sand casting.
If you're only going to make a small number of parts a loose pattern should suffice, as opposed to putting it on a match plate. Anything with cores is much more involved. Draft (release angle) should be a minumum of one degree everywhere, more is better- like 2-4 degrees. If you're casting aluminum, plan on a shrink of about .012 per inch. In other words, if you want the finished part to be 4" long, make the pattern 4.048" long. Softwood is ok, laminating it will help prevent warpage. Try to not create sharp edges or corners. You can buy fillet wax by the roll, it's like a strip of wax in the shape of a cove mold. Press it into place, the pros use a ball bearing silver soldered to a steel rod to burnish the wax, you could improvise something. Heat the tool, rub the wax to stick it in place and make the fillet consistent. Finish the pattern with urethane or something like that. Check out this site:
http://www.kindt-collins.com/ I used to have some dealings with a foundry in Cambridge,Ontario, but it's been years... Probably best to first find a foundry that's willing to cast your parts and seek their advice.
