Well, I got a short haired cat called Jasmine who actually enjoys baths if I put her on my lap while washing her, tho she's full grown. Of course, that gets me wet from head to toe, but at least it keeps her happy.

Here's how I do it,
1. I fill a tub with warm water and I get a large-sized cup to use to dip into the water and pour gently onto her.
2. I then pour the water onto her back slowly with the cup just a little bit above her fur, so as it doesn't hit her hard and it doesn't make any noise.
3.While I do that, I rub the water into her fur while talking to her in what I hope to be a soothing voice. I mean, I dunno if my voice can be soothing, but it
seemed to work. >.>
4.After she is wet all over, I put some soap onto my hand or on her back and rub it into the fur on her body and tail.
5.Then I pour some water onto her back again in the same way as before until all the soap is gone.
--Steps I take if her face is also dirty--
6. I put a little bit of soap onto a wet cloth and rub her face with it
7. Then I take another cloth with only water in it and rub all the soap out of the fur on her face.
^Yup, all that with her on my lap.

I usually wash her with soap 3 times over, because she is a VERY dirty cat and often just flops into muddy puddles.

Of course since your cat is long haired you must, as said in the posts above, comb her before and after.
Also, like I said before, that's just how I do it, and Jasmine is very, very forgiving and she really puts up with me a lot. (Even tho she scratches me to smithereens if I try to wash her in a tub and not on my lap.) If you have a more aggressive cat it'd probably be best to do it another way, or with a lot of protective clothing at least.
Though... It's hard to imagine such a beautiful cat hurting
anything. She like such a sweetie! I just love the light brown around her nose!
