What do you want to know about? There's a lot and a little to know, all at the same time, and just about all of it is common sense.
Like cats?
I don't know how it works in Foreign-land, but tenant-landlord contracts tend to have illegal clauses in them. Where I live, it is illegal to forbid tenants from owning pets, yet almost every contract includes a No-Pets clause. This is mostly to scare people who don't know any better. Landlords do not like it when tenants have pets like cats/dogs (increases wear on the furniture, as well as odors and stuff - they have to replace stuff more often if you keep a non-caged pet) so uh, keep that in mind.
Also, while cats are normally a safe bet, if you're living alone and working full-time, consider the fact that your pet is going to spend that much time alone every day, and that just doesn't work for dogs. Cats seem to be okay with it, but kittens not so much. Even when living on your own, you have to think about more than yourself.