I must say though often what will work for your bub, might not be something you are comfortable with, so my advice is try anything and everything until you find what works.
Some me parents decide to go down the CC route but find their bub throws up from the experience, so that method clearly doesn't work for the baby.
Then there are parents who try gentle methods and find it makes no difference at all as that particular baby needs more of a tough love approach.
theres a great site called baby sleep site which has amazing sleep articles from no-cry methods to CC methods and everything in between.
Remember you can sleep train without leaving bub alone but also by stopping bad sleep associations such as feeding or rocking to sleep, this worked for us. It wasn't as quick as CC, but was definitely quicker than continuing to rock or feed to sleep.