If you introduce a new kitten make sure the older cat gets plenty of hugs. Expect a load of swearing, hissing and general fuss from the big one for a while. Usually they come to an understanding between themselves reasonably quickly (a week or so). Sometimes this happens a lot quicker than they let their humans know!

DON'T try putting the kitten in the older cats 'space' eg bed, special cushion. It's just asking for trouble. Similarly with feeding. They won't just share plates to start with.