My 16 weeker has gone from sleeping 7 til 7 to waking up three or four times in the night. I'm assuming this is the four month sleep regression and at some point it will right itself.
I've read the article about the four month sleep regression on babysleepsite.com, which talks about sleep associations, and I don't want to create associations that aren't there now by the way we deal with her wakings at the moment.
She isn't hungry when she wakes, she just wants to shout and sing. 
She self-settles when put into her cot at 7, but finds it harder in the middle of the night, and to get her back to sleep we're putting her music box on and sometimes feeding her. I don't want her to get upset, but I also don't want to create sleep associations like comfort feeding her, picking her up etc, in case this affects her ability to self-settle the rest of the time. .
Any ideas?