This is stuff that I found to be really useful my first time using polymer clay. Like everything else on the internet, for every source that said, "Do this.", there was another source that said, "Do that." I just picked what made the most sense to me, but it's not necessarily the best way or even the right way. It just seemed to work for me, for now and is probably subject to change as I learn more. This is not a list of everything you need to know, just answers to the biggest questions I had.
For a list of everything, or almost everything here are a couple of sources I found to be quite useful:
The first thing that was news to me is polymer clay is a plastic. I honestly didn't know that. That's how much of a polymer virgin I was. But it was important for me to set aside preconceived notions based on traditional clay.
Based on information regarding ease of use, availability and durability of the finished product, I went with Premo Sculpey.
I found out the hard way to give the clay a little squeeze at the store, that might not be a good test for some of the firmer clays, still a virgin on those, but the Premo Sculpey should be easy to press in a little indent. I had to exchange one of the first blocks I purchased. It was rock hard and crumbly right out of the package. I tried working a small piece to condition it, but to no avail. I still thought it might be me, being a virgin and all, but nope, new block worked as expected. It was no hassle to exchange, but making an extra trip when you want to start a project sucks.
I mostly followed the advice on The Blue Bottle Tree when it came to baking, except for that bit she says is the most important, about testing your actual oven temp. There's no trying to teach some people and I'm one of them. But I did pick up four 6x6 inch glossy white ceramic tiles, not just for baking but also to use as a work surface, from the local home improvement store and a couple of packs of 8x8 inch disposable aluminum pans. I already had the binder clips.
I'll take her word that by baking my clay on the tiles, enclosed in the aluminum pans with the oven on convection that I was getting nice even heating. I didn't do any sort of scientific testing to determine if that was actually the case. What makes this method all worth it for me is the odors are contained by the pans. That was something I could definitely tell. When I removed the top pan all the cured polymer smells came wafting out. I run the vent fan during baking and take the pans still clipped together outside to cool. It's my understanding that drastic temperature drops can crack the polymer, so this probably won't be a winter sport for me.
Polymer clay flattens on the bottom while baking. If you are making round beads or unicorn horns you can accordion fold a piece of paper and set the pieces in the fold, but paper will leach the clay, so only place pieces right before baking. Also clay baked directly on a flat surface will develop a shine, so use parchment paper over any baking surface.
I found a lot of conflicting information on finishes. I decided to go with the school of thought that polymer clay does not need a protective finish unless it's been painted or a high gloss finish is desired. And don't ever use nail polish as a finish. There's lots of info about sanding to finish a piece. I haven't assimilated it yet, so still a virgin, but someday I'll probably go there.
Another tidbit that I came across repeatedly is that eye pins stuck into clay, even if glued after baking will eventually come loose. One thing is to use a head pin that runs all the way through your piece, the other is to put a little bend in the end of the wire and hook it in, this video shows both of those. For the couple of things I've done, I've found securing the clay around the 'eye' of an eye pin worked best, and then wire wrapping the free end after baking and cooling worked best. Of course my method wouldn't work if you tried to insert the 'eye' into a finished piece.