Here's my thoughts on the matter

1 - Air Conditioner on
(noticed this one real quickly - turning it off on the morning commute with the temp isn't as high really saves on the FE. Its too hot to do it on the way home though)

2 - Hills
(going uphill really drops the FE fast. I'd stay away from hills as much as possible.)

3 - Jack Rabbit starts
(much better to start slowly. If you can pick up speed going downhill thats even more of a plus.)

4 -Wind Resistance
(once I get above 65 I see a pretty big drop in the FE)

5 - Weather (temp and rain)
(put it at 5 just because it forces me to use the AC when it gets hot. Haven't had the car long enough to notice a difference in the winter)

6 - Weight in trunk
(just seems to make sense that less weight makes it easier to get higher FE)

7 - Stop and Go driving
(it messes me up when I can't get my HCH to go into auto-stop all the time. This especially happens when the stop and go traffic is going uphill. That's the worst!!)

8 - Cruise control use
(put this a little lower because it seems like I can regulate almost as good as the cruise. Probably would help on a long trip so I don't have to be so focused.)

9 - Low Tire pressure
(This might be a bit low for this one, but it seems like there's a lot of discrepancy regarding the issue.)

10 - Full tank vs. half tank of gas
(don't know enough about this one yet. I'll have to research it a little.)