Most birds are pretty easy to entertain and some are more demanding, even in the same species of bird! I have one very cuddly, fun-loving bird and one destructive, tempermental bird. Of course, one was hand raised and the other I adopted from someone who couldn't care for it...so I think the more love you show them, the more they'll show back.
Everyone has different views on leashes, wing clipping, foods, vitamins, showers, etc. I think the easiest way to figure out all of these things is to see what your bird responds to best. Some birds like certain things and some dont.
The most trying of tasks with a bird is cleaning the cage. I line the bottom with newspaper and just dump the tray and replace the newspaper every other day. I have small birds so they *USUALLY* don't make that big of a mess (as far as poopy goes). Seed guards go a LOGN way though...otherwise you'll be vaccuming for days.
Cockatiels are like potato chips, you can't have just one!