When faced with an alien invasion, the first thing to do is PANIC!
It will probably not take long to see whether they are friendly or not. If, when their spaceship lands, they do nothing for ages, then there is probably a 35% chance that they are friendly. They could be sitting and observing us, the humans, to see whether we are friendly to them.
If they do turn out to be friendly, then Great! Swap new medical discoveries with them, like the cure for cancer and the common cold. Show them the way to Amarillo. Treat them to a fantastic traditional Earth meal. But be extremely careful what you give them. Do not give them anything too hot or too cold, or too funny-looking. They might: become confused/upset/think you are trying to kill them! On second thoughts, maybe get them to feed you one of their delicacies then hide it in your pocket when they are not looking.
But, if they approach the Earth and start blowing up the buildings or land and start melting the tanks surrounding them, then there is a 99.9% chance that they are unfriendly.
The trouble with unfriendly aliens is that they may have just spent the last few light years travelling to reach us, in which case, not only are they unfriendly, but they will also be very, very cranky.
So, How do You Survive, Unfriendly, Sleep Deprived and Cranky Aliens?
There is no guarantee that anything will definitely work, but there are a few things to try and some things to definitely avoid.
Under no circumstances are you to make your way towards the landing site and try to get onboard with a computer virus on a USB stick. This action is classed as Very Very Dangerous.
Similarly, Do Not, repeat: Do Not, try to befriend an Unfriendly Alien.
These two actions alone, if completely avoided will greatly increase your chances of surviving.
A great tip in a case like this is: RUN AWAY! Run as far as you can in the opposite direction. Do not get in the way of, or make eye contact with anyone who is headed towards the spaceship. They have either got a USB stick in their pockets, or they have been hypnotised by the aliens' space probe. Either of these things means that they are beyond your help any way.
Do keep any stray pets that you find along the way, or join a raggle taggle group of misfits, especially if they have a guitar player among them and a large van which is headed in the opposite direction.
Ah, I hear you say, What if you can't run away? What if you get caught?
Sometimes, standing very still will help you a great deal. A lot of aliens will come within a hair's breadth of you ... and then go away for no reason!
This has been a great trick which has been used by a lot of alien survivors.
Try casually throwing any household items that you can at them to see whether it will melt them, irritate them or make them very very happy. You never know, after all, they are aliens, they might never have come across fizzy pop or jelly and custard before. It never hurts to try.
If there is no other way, you have been caught and trapped on their ship, then I'm sorry, but the only thing to do is to try to blend in as much as possible. Be helpful. Because they are so slow and cumbersome, they might appreciate someone who can bring things to them quickly or reach up to the top shelf on their spaceship.
In time, they will learn to see how wrong they were and that humans are not the horrible war mongers and general bad boys that our radio and television transmissions into space would have them think. They might think that we are very useful after all.
They might even cancel the bigger invasion that they had planned for later in the year! You would be doing humanity a very big service!