DD1 is 3.9, shy, stubborn, sensitive. DD2 is 11 months. DD1 has found her sister's arrival quite difficult, although she clearly loves her sister and now dd2 is a bit bigger dd1 makes the effort to play with her (bouncing on the bed, or playing the keyboards - little things), and will always try to comfort her (singing songs in the car, telling her things will be OK if she is crying etc). SO there are lots of positive signs, but dd1 is often a bit rough with dd2, and occasionally does something that she knows will hurt her (pull hair - which of course dd2 does all the time).. These incidents are usually triggered by me (in particular) paying attention to dd2 - the main problem is that dd1 doesn't really seem to understand that dd2 is a baby and that she will fall over if you push her too hard etc. DD1 is quite volatile around dd2, so she'll have a day where she clearly loves her to bits, and another where she doesn't want her to be here at all - I guess that's to be expected and I don't expect a small child to be consistent. If she hurts dd2 (as I say, 95% of the time by taking sufficient account of the fact that she is a baby) then she apologizes, or cries.
It's not a terrible problem by any means, but it is an issue. I don't have siblings myself, so I don't have much sense of what the normal parameters are. Is there anything I can do to improve things? DD1 gets a lot of 1:1 time with me, praise for good behaviour towards dd2, treats taken away for bad. Any thing else I should be doing?