dont EVER set any components on carpet... i learned the hard way, most of the time nothing happens, but every now and then something will get fried
dont over apply the heatsink compound, just a dot between the size of a pea and a BB will do the trick, let the pressure of the heatsink spread the paste around, dont touch it with your finger because that gets grease, dirt and anything else you have on your finger in it
when you first fire it up, keep it in bios and watch the temps, make sure the heatsink is seated properly
dont do "half" tests, make sure everything is hooked up, dont just hook up the psu to the mobo and turn it on, put everything together and give it a try, but i recommend putting everything together outside of the case, so problems can easily be diagnosed
most important.. have fun!