Drink hot beverages
What? Hot drinks when all you want is an iced cappuccino? Yes - drinking hot drinks will make the temperature seem lower. It might not be what you want - but it will have a cooling effect!
Plants are not the only living things that need water during the hotter months! Keep a spray bottle nearby and give your face a spritz every time you feel like you need it.
Eat lots of fruits and salads!
Try to avoid fatty foods and go for fruits and vegetables instead: they will leave you feeling less bloated and they contain more water as well, which will contribute to your overall hydration.
Turn off your computer when you're not using it
Computers can get really hot and leaving them on when it's not necessary will only make the temperature rise even more!
Don't wear tight clothes
They will make you feel sweatier.
Avoid caffeine and alcohol
Alcohol- and caffeine containing drinks will dehydrate you - and staying hydrated is necessary to survive the heat.
Turn off your lights
Just like your computer, lights work as a little heater - make sure to turn them off so this source of warmth gets eliminated.
I can't close my window (it's being fixed but for now, it's really annoying) so I've been an absolute hipster for the past few days: I've wandered through the streets of Amsterdam, hopping in- and out of coffeeshops (the ones where you can get actual coffee;)), ordering iced chai teas and cappuccinos non stop. Escaping small rooms won't make the rooms cooler, but it might cool you instead.
Cool your wrists
Cooling your wrists using tap water or even better, ice cubes, will take the heat away for a few minutes. This works on your ankles and behind the knees as well!
Drink some water before going to bed
This will keep you hydrated during the night - don't drink too much though, because nobody likes a person who keeps on running to the bathroom all night!
Don't think about the heat
Stop repeating the thought 'I'm so hot, I can't sleep, I can't function, I'm so sweaty' - it will only make you hotter/more sleepless/less functioning/sweatier!
This couldn't have been a more straightforward suggestion and some have school/work, but if you're just staying in your house sweating, you could also grab your bath towel and sunscreen and take the train to the beach or visit your local swimming pool!
Try to enjoy it
Even though the constant flow of sweat escaping from your body is extremely annoying - you're going to miss it when you're tucked into your bed, freezing in the winter.
I hope this little list of tips will help you survive these unbearable temperatures!