I usually just torque them "to feel"... tight enough..
Don't got a torque wrench.
i always tighten them by my feel also. several steps: 1) figer tight while its lifted, 2) torque em up little bit more while the wheel is touching ground slightly, 3) final muscle work when wheel is on the ground completely

oh, little bit off topic but still related - always check your lugnuts' torque after safety-state-checks or any shops which take your wheels off!!!
one day after my mom's car had a safery inspection it was making really funky sounds from the front. we changed brakes 2 days before that so we thought something was messed up with brakes, but the car passed inspection. the problem WAS = the moron, who ever inspected the car used air wrench (duh) and didnt tighten lugs tight enough so the left front wheel was actually held by like 3 out of 5 lugs