How Do I Teach My Four Year Old to Love and Cherish His Baby Sister?

You have to put yourself into your son's position and imagine that wow I am no longer the center of the 'universe' and how dare you bring something home that takes attention away from me and why don't you pay all your attention to me, am I not cute anough or, that thing makes alot of noise and even others are paying it more attention. Maybe if I am louder and......
You get the idea. I'm sure you know this on one level but the reality is the dynamics of the family has permanently changed. I felt the same when my 2nd son was born and my first's innocence was no longer there. You'll find time to spend exclusively with the first born and that time should be held sacred. Find a trusted friend to care for the daughter and have fun. Maybe going out for icecream or to a park.
I have a friend who has a just one child and I might be biased but I don't think only children mature too well with out finding out in a hard way that life things are not just handed to you. Sharing and learning to work well with others really is something to be valued.....

Hi, my kids are two years apart and when I first brought my daughter home, my son wanted nothing to do with her!!! One day a Franklin (the Turtle) cartoon came on where his mom brought home a new baby, and all his little friends were jealous because he was so lucky to have his own new little sister. Right after that cartoon, he came over and looked at her, kissed her on the forehead and ever since then, he loved her. I recommend finding a video that helps them deal with this new little intruder.:) It wasnt any thing I did on purpose it was just great timing. BTW, my kids still get along like best friends they are now 10 and almost 8 !!

I would do a behavior chart. Most things he is doing is impulsive and to seek attention, even if it is bad attention.
If he can have a visual then he can see how he is doing each day. Rewards for helping and being kind, consequences for bad behavior.
I would also include him in helping with his sister. Make it a huge big boy job to help her with feeding, getting a diaper for you, teaching her to make funny faces.
Then I would put on a calendar special days with just you or just your husband so he has something to look forward to and realizes he will get your time.
Another thing that helped my daughter when her brother came along was getting out the baby pictures and home movies of her when she was that age so she saw I had to take care of her that way too and she was young once too.
You aren't losing him, he is testing boundaries to see if rules don't apply anymore. You have to be compassionate to his feelings however really be hard on him for it being unacceptable to be mean at any level. For the safety of your daughter and for him to learn that it is never okay to be mean to anyone.
I don't think there is a set timeline when a child accepts a sibling. I think each child is different and all you can do is be consistent and let him know that he has boundaries and he needs to stay in them.

This too shall pass. I recommend the book Siblings without rivalry. it really helps you get into the mind of your son and see what a HUGE adjustment this is. I think 2 months is an in accurate expectation your doc set. You may already be doing this, but don't pay extra lovey attention to your daughter when he is around. he is listening to EVERYTHING you say to her and do with her and comparing it to how you treat him. it's hard because he gets disciplined and she gets sweet talk. talk to him about it. i used to do this and that with you when you were a baby, and even though i say no and please don't do this and that to you now, i love you even more than i did when you were a baby. and i'll say those same things to her when she is four. let him help if he wants to. help him feel important to you. he feels replaced. praise him a lot. let him overhear you saying praising things about him to the baby and others. let him have some preferencial treatment during this period, she won't care and it will mean the world to him. he is having to share you and dad for the first time ever and he probably has a lot of intense feelings about that. my son was 3.5 when my daughter was born and it was a big adjustment for all of us. when she was about 7 months he told me he wanted to get rid of her so we discussed our options and then he decided maybe we should store her in the closet, so i acted like i was putting her up on a high shelf in my closet and said, i don't know, do you think she'll fall? and he decided we should not leave her up there. make special time for you and him. go to places he likes to go, just the two of you. an hour will mean the world to him. when you are alone, say, i bet you wish sometimes that your sister weren't here or would go away. tell him it's ok to feel that way, it will mean a lot. tell him you would feel that way. tell him sometimes you miss when it was just you three too, but then you are really glad she's here too. tell him what fun things they'll be able to do together when she gets bigger. when he is acting out towards her, translate it for him. oh, wait! i see you feel like hitting her, but that won't work. you can hit this pillow. are you needing something right now? would you like to come sit in my lap? maybe next time you could just say, mom, i want to sit in your lap! and if he is able to do that instead of direct his feelings toward her in a negative way, hand her off right away and reward that with some personal time. other good books are Why Do You Love Me? by Laura C. Schlessinger, and I Used To Be the Baby by Robin Ballard. we read these a lot and they sparked some good conversation at bedtime when we were lying in his bed just the two of us. this will pass, and you will see your bright shining boy again. he just needs your help right now, which is hard because you have an 8 month old too! take care and good luck

One thing that worked really well with my daughter was giving her special time alone with both my husband and I. She was very jealous of the attention her little brother was getting when he was an infant. At least once a month my husband and I each go and do something special with her. We can usually tell when she's ready for her special time. She doesn't seem to feel threatened by her brother now and they have loving relationship for the most part. Good Luck!