I have done 6 builds/0 DOA. It's mostly chance, but I do have some easy suggestions.
First is to go ahead and unbox your parts that have static bags. They can be handled in the bag as long as you don't do any physical damage (Dropping, smashing, etc). In general you want to hold the parts by the edges (look for places where there are no components to accidentally touch, especially anything that looks like a microchip. Microchips are the most sensitive ESD parts. For now I would just grab the edges and lift it out of the box, and place it firmly on the motherboard box or another similar surface.
Go on as usual and prepare your case before even worrying about your motherboard. Add the standoffs and make it ready to just drop it in. Once it looks good you will (at this point) start to check your self.
three things to do)
1) make sure you're not in excessively loose clothing, and that socks are off. socks on floor = static, and loose clothing rubbing on it self is the same. Just a precaution, don't go crazy you don't have to build the PC while naked or anything.
2) make sure you are ready to do what you need to do. Lay out your processor box, memory, etc at hand, so you don't have to get up and get detracted. Again it's just a precaution to make things go smoothly as possible. Don't fret if it doesn't exactly go as planned.
3) at this point you want to make sure you've at least discharged any extra charge you have. Part of ESD is that the charge is so small that you can't notice it, so it's not a guarantee, but the general process is to find something large that is grounded (I usually use a kitchen sink/metal contact) and hold onto that for a minute or two. then go ahead and touch your case as well (hands on metal) to even out any charge between you two. At that point it should be pretty minimal, and it's time to remove your mobo from the bag.
A lot of people like to build & test the motherboard on top of the motherboard box/esd bag. It can be useful for troubleshooting, but I like to add the few parts I need to & then get it in the case asap. I would add the CPU, cooler, Ram and then go ahead & touch the case again (Grounding your self) before picking up the mobo (by the edges, touch as little of the metal on it as your can. silicon base is fine to touch) and placing it into your case.
Then I'd just screw it down gently & make sure i'm not over tightening it at all (can cause shorts, just screw it lightly until it's snug, then give it another 1/8 turn, should be just snug not tight), add the GPU & power cables, etc, and at then add power when it's finally completely ready.
In short, there is just a little special care you need to take. Just be sure you do something to discharge static and ground your self, then to just be aware of any contact that would undo that precaution. It's not very hard to be careful. If you feel too nervous to handle that than you can always get a static strap at your local electronics store (radioshack?) and ground your self to the case.
It is absolutely true that you should handle parts by the plastic.