Don't be too scared... just watch a few un-boxing or system build youtube videos and you'll see that they are remarkably tolerant of sometimes seriously bad handling. That said, just be careful...pick up by edges and avoid use of heatsinks, connectors or other board-mounted devices as 'handles'.
And while you could probably get by without a wrist strap using some simple precautions will go a long way to prevent static damage. First, keep the board in the static-safe bag it shipped in until you're ready to put it into the case. Second...before sticking a hand inside the bag to get it out discharge any static charge on your body and clothes to something big and metallic like the case itself by touching it for a few seconds. Third...stand still while handling it, that is don't shuffle your feet or move about.
And whatever you do, hold tools firmly. I can't count how many times I've heard of people dropping a screw driver point first onto the motherboard while installing the screws.