Basically, it the outside temperature is colder than inside, you need to get the inside air outside and the outside air in! So, closing windows won't help- it'll actually make it worse as you're creating a greenhouse effect. If you had air-con running, you would need to seal the windows to stop the air-con working overtime.
Putting foil on the sliding door to reflect heat should work, but painting the other half black I don't understand as that might make it absorb heat.
A fan on it's own will not actually cool down a room. It is a common misconception. The fan must either be used to duct the heat out of the room like an extractor fan, or create a breeze which works by cooling you by evaporation.
There's a simple experiment which shows fans do not cool down air directly. If you have a fan and put a thermometer in the air flow, you will not notice any temperature drop in the thermometer if the fan is on or not. If however you put some water on the thermometer (simulating sweat) you'll see the temp[erature drops. The other reason a fan cools us down is we are at about 37 degs C and the outside air is lower, so the fan blows a stream of colder air over us which takes heat out of us.
One thing to do is to sit in your fan flow and spray your self every now and then with a plant sprayer/humidifier with water. This will act like super sweat and cool you down. You can also use the same trick in bed at night.