Have your air conditioner checked early next spring - before you need it. Change or clean air filters. Try to shade your outdoor A/C unit! Make sure air can flow around it (clip those bushes.)
Likewise, make sure doors and windows fit snugly and aren't leaking expensive A/C to the outside. (This will keep out roaches too - a bonus.) When you replace windows or doors, get the best insulated, best performance new ones you can afford.
Moving air feels cooler. With a fan, you can turn up your thermostat and save, since a fan uses less electricity than a compressor. Ceiling fans are a good idea, but portable ones work too. (Try an old-fashioned hand-powered fan like Scarlett O'Hara's: relief at hand when trapped in, say, a hot restaurant. People will stop staring after a while - then ask to borrow it.)
Plant a deciduous tree on the south or west side of your house - watch your A/C bill drop. Save trees. Water trees. Trees are our friends - go hug one. Any time you stop the direct rays of the sun striking your home (at 107 degrees it's assault and battery!), you save energy to cool it. So plant vines on the west wall of your house, or tall shrubs, or a tree.
When you can, add awnings, blinds, patio covers, pergolas, porches (wonderful, traditional porches!), or sun umbrellas to shade your house or the area around it. Blinds on the outside of a window help more than blinds on the inside. Either way, shut them when you're not home or in the afternoon, when it's hottest.
Think Light and Cool:
Light colors reflect light and heat better - dark colors absorb it. One of the best energy saving things you could do would be to climb up and paint your roof white! So can you? When you re-roof choose light-colored shingles. Paint your house a light color. Buy white blinds. Light colored pavers stay cooler than dark ones. Ditto lawn furniture...
Check your attic. Add insulation. This is relatively cheap and easy, paying for itself quickly in energy savings. Walls are harder to insulate after a house is built, but sometimes it's not that tough - worth checking.
Image borrowed from Star Maker Machine where there's a song about a porch
There are a number of tricks our ancestors used to feel cooler... or to think they felt cooler, which works just as well, right? Fans are a big one. Moving air! Also simplify your rooms: put away the knicknacks, take down heavy curtains, give your home the bare style of a lake cabin. Definitely remove rugs, if you can, because walking bare foot on bare boards or especially on tile, seems and is cooler. Shade your room by drawing blinds or dimming lights. Lighten colors - cover the red velvet coach with a white(ish) cotton throw. "Cool" colors like blue and green translate into a few real degrees on the thermostat compared to "hot" ones like red or orange. I bet one of those desktop fountains with trickling water would help. Dress coolly. Drink icy cool drinks with mint in them. On your porch. (You know, at dawn, when it's only 90 degrees.)