Well...I bred them years ago and now only have one cockatiel..but she's a bit of an oddball one.
She will ONLY eat the complete feed (the one that is in the shape of fruit pieces and is fruit flavored)...won't eat seed, treats, nothing else! Even when my friend's bird comes to "visit" (stays with my bird when they go on vacation) I have the seed and all his food and treats in the cage with them both, and she still won't touch them.
I think it's good though when they will eat a variety of things. Cuttlebone will help with the beak as well as what they eat (seed/feed/etc.) helps wear it down.
Most bird cages have a wire bottom to separate the substrate from the birds...so it doesn't matter what you line it with as long as it's easy for you to clean up (I use paper towels).
Mine seems to molt about once a year. Her wings I've trimmed only about every 3-4 months if that much...but that also depends on the bird. When the flight (long outside) feathers get long...trim them. I don't cut all the wing feathers as the shorter ones you can leave they "hide" the cut marks on the flight feathers (looks nicer).
Definitely make sure you have a variety of perch sizes/thicknesses to exercise their feet so they don't get cramped. Also make sure to keep up on checking their toenails...they need trimming as well.
Cockatiels are generally social so adding another later is not usually a problem. However, more than one and they won't bond with you as much.
Make sure as with any bird you don't have the cage in a drafty area (I keep a throw over my cagetop since I'm in south Florida and the a/c is always on...that way she can have parts of her cage she can get away from any occasional drafts).
If you want a bird for a pet...pay a lot of attention to it! Mine sits next to my desk in my main room so she's always in the middle of the action. Except for the poop, cockatiels are great little birds to have hang out by you outside the cage and they love to be around their people.
That's all I can think of!
Oh...try to definitely get a hand fed/raised one. Even if it costs a bit more, it's worth it! Make sure you play with/hold the bird if you get it from a pet store...many might have been hand fed but not had much attention so they are still scared of people. Private breeders, or pet stores who get their babies from breeders that take the time with them are the best. Especially when you consider you have to trim their wings/nails and if the bird is good with people it isn't as stressful on them (and they have less tendency to bite too, hehe).
Good luck!
This is Pearl...she's about 2 1/2 years old (picture was when I first got her...the breeder cut her tail off since the other birds chewed it and I hadn't trimmed her wings yet...now she's gorgeous with a full tail!).