Summer driving 95+° F.

[Leebaby]

2000 RX300 MINT CONDITION.  212k miles.  I'm looking for your suggestions, tips, wisdom...to keep her running strong ALL summer.   Oil, transmission, brakes, a/C, driving techniques, etc...? Welcoming any ideas..  this is the busiest time of the year for work, and I drive more than usual. 

[Lexus Owners Club]

Certainly an idea to change all of the fluids and filters to ensure reliability.
Also, driving style is always best to drive gently to avoid overheating and also to conserve fuel especially if running the air conditioning constantly

[RX400h]

I peruse the maintenance manual every so often to see if formerly completed requirements are due again. I also keep a small notebook with maintenance description, date, and number of miles. An Excel spreadsheet is another option. Engine air and cabin filters are checked and often replaced in 10,000-mile intervals.
 Every time I change the oil (at about 5000 mile intervals), while letting the oil drain, I spritz the engine bay with water and wipe with a rag or paper towel. Then I spray Armor All (non-glossy) on hood and door, rubber seals, as well as the plastic interior surfaces, and wipe with a rag.

[Bykfixer]

When driving in summer I try to keep a bigger gap between the front of my vehicle and rear of the one in front of me. More consistant air hitting the radiator. 

I also keep a sunshield in the window to greatly reduce interior temperature when entering the car. 

In winter I let the car run for a few minutes before driving it in order to allow the oil to warm up. 

If it does mostly city driving I try to take it onto the interstate on occasion to drive it 20 minutes or so at a steady speed. Drive 20 miles or so, turn around and drive back home.