We live in a mobile on a basement, in a part of Canada that gets hotter than Texas for most of July and August.
Here are some things i do.
-If you live in a humid area, get a dehumidifier. Not only will the mold spores in your house hate you, it will feel a lot cooler is you can get any sweat to evaporate.
-Open windows at night, close them during the day.
-Stay off the south side of the house, and don't open a single door or window on that side if you can possibly avoid it. (can't even walk on my Southern deck without shoes! imagine how much heat that lets in if I open the door)
-ceiling fans, ceiling fans, ceiling fans. Put them in every room.
-If you can't put a ceiling fan in (say, because your bedroom ceiling is 7'6" and your DH is 6'5", not that i would know

) use oscillating fans just to move the air. Also, using window fans to pull in cool night air works very well. Remove them and close the window and drapes during the day.
-If your drapes/blinds are lightweight and you can see light through them, get heavier ones.
If you have a covered porch, hang cotton blankets around it, soak them down with water from the hose. Grab the oscillating fans and sit out there all day drinking water and getting the kids to continually spray them down. Any breeze blowing through the blankets will be blissful. Open windows that open on to the porch
-if you have a basement, point a box fan up towards the upper levels from the basement. Put it on the stairs, and use some items on hand to angle it cleverly.
-Drink water! No coffee, no beer, no tea, no iced tea. just water. Add a little lemon if you get tired of the taste.
-Don't cook inside. A crock pot is very happy on the deck all day. An electric skillet can also be plugged in outside. BBQs are obvious, but make good use of one
-Don't turn the computer/TV on during the day. They pump out a lot of heat
-Hang laundry to dry. I don't have a lot of money on dryer electricity, but i do save a lot on not running A/C. If you're really clever, hang laundry on an indoor rack and put an oscillating fan in front of it. Voila! Swamp cooler, and dry laundry. Or, if you have central HVAC, turn the fan on and hang the laundry over heating vents.
-If all else fails, shop. Go to the mall, the grocery store, whatever. Don't stay in there too long though, the heat seems even more unbearable if you have been sitting in freezing cold A/C all day.