Regardless of weather I have to work at 6am, 8am, 2pm or 6pm I like to wake up 2 hours before I have to leave for work.
I have a pretty rock solid internal clock and have probably been woken up by my alarm less than 100 times in my entire life. I always set one (it's looking a the time right before I go to bed that allows me to wake up naturally, or at least that's what I tell myself). I usually wake up about 5-10min before the time I set my alarm for.
I NEVER use the snooze button. NEVER.
That's how you train yourself to not wake up properly and/or not even respond to your alarm when it goes off.
First thing I do is make coffee. Then I take my coffee and sit at my computer and read the news, catch up on jazzfanz.com, etc. I really like to take my time waking all the way up like this.
After 30min or so the coffee is kicking in which means it's time to poop.
After that it's shower time.
Depending on how much time I have left I might read some more news or play a PC game for a few minutes. If not enough time I go right into preparing my lunch bag and hitting the road.
I don't like to get to work so early that I have to hang around before I start. I'm extremely consistent in when I leave and when I arrive. My current commute is very predictable so I usually get to work 5-10 min before I have to be there, clock right in and start working. When I've had a longer more unpredictable commute I generally arrive 15min before I have to be there, but same thing, get there and get to work. If that amount of buffer isn't enough to keep me from being late then I'm willing to risk it, but in my entire adult life I've probably been late for work less than 12 times.