Introducing kitten to cat...

[Tabbylady]

One of our DCats was run over about 4 months ago. We had had her and her sister since they were tiny- we'd rescued them out of a bin.
Our remaining DCat pined for her sister for a long time. She's 18 months and still very kittenish
We have just agreed to take on a female kitten- she's 4 weeks old so we should get her in about a month.

I have googled and googled but all advice is conflicting- how do I ease the passage of DCat and DKitten meeting? I don't want them to fight and am really hopeful that DCat will enjoy having another furry friend to play with!

So far I have feliway and a new litter tray. Help appreciated!