-Mixed gender houses tend to have the least arguments and drama I find, on both sides.
-If you're unsure if you trust someone don't live with them.
-if someone is irresponsible with money or in general, don't live with them (trust me, it could end up costing you money like it did for me)
-If you're into partying don't live with people who aren't if you're not going to be considerate with noise and vice versa don't live with heavy party goers if you hate noise.
-Don't move in with someone who doesn't even know how to use a washing machine or bother to wash things, your house will be a disgusting mess and you will hate it.
-Make sure whoever you choose to live with they are someone you can go to with a problem and they won't get defensive and will understand your point of view. Otherwise you may find yourself in a constant battle if someone isn't respecting your point of view or how their behaviour may affect others.
I made a mistake with every single one of those things, don't make my mistakes. I've loved living with some of my housemates, but on the other hand I've also been made quite miserable in several ways by a couple of them for varying reasons.