Hiya 
In your case GW needs to start with feeding to sleep. Getting baby into the cot to go to sleep is for much later.
You are aiming for something not dissimilar to the Pantly Pulloff (google will explain more). You aim is so that baby is being cuddled to sleep, not fed to sleep.
Assuming you start off at the point whereby you feed baby to sleep, then keep baby in your arms until fully unconscious and floppy, then place baby into cot. So the first step is unlatching baby from nipple about a minute or two than you normally would. Then still cuddle to sleep. The ultimate aim here is that you can breastfeed until baby has stopped feeding, unlatch and cuddle to sleep.
Then the aim would be to just cuddle to sleep. So maybe feed baby at start of bedtime routine, not at the end. At the point of going to sleep, breastfeed just to settle then aim that the falling asleep bit happens in your arms, not being fed.
At that point you can look back at the progress you have made and realise that you no longer need to breastfeed to sleep, you are cuddling to sleep instead.
Then the aim is to make being cuddled to sleep less vital. So you might start cuddling baby to sleep in the breastfeeding position initially. Change the hold slightly so that you are cuddling to sleep in a cradle hold but not being BF. Then try cuddling to sleep with you standing up - this is an important stage since you'll need to be standing to put baby in the cot ultimately.
Then aim for a mix-and-match approach to the cuddling to sleep. Sometimes in a cradle hold, sometimes over your shoulder cuddle, sometimes Dad doing it, sometimes on the chair. Key is to make baby less relianet on a specific thing happening to go to sleep, just that baby needs your presence and comfort (or Daddy's), not a specific 'thing'.
So all this ^ has happened before you start the process of getting baby to go to sleep in the cot.
So at some point during this cuddling to sleep, start putting baby into the cot a couple of minutes before you normally would. Instead of unconscious and floppy, just before this stage. Baby will still be asleep, but not so asleep.
Over time put sleeping/drowsy baby into the cot sooner. It might be you have nights were you put baby down in the cot and its too much, baby wont settle in the cot. Not to worry, just pick up and cuddle again (at this time baby will only need a cuddle to sleep now). Once settled try again.
Get baby used to being put into the cot when they are asleep, so they know its happening. But if ever any distress is created, just pick up and cuddle then try again.
Its all about trust.
Baby needs to know that while there will be changes towards indendant sleeping, that they will not be in any distress and if ever they need more comfort, it will be there. However whilst the comfort is ever present, so is the drive towards ever more independent sleeping.
After all of this ^ you are aiming for the point where baby will tolerate you putting her down in the cot when it is sleep time, and comforting her in the cot. With you staying and comforting until she is asleep.
The next stages are with the aim of reducing the amount of reassurance needed to go to sleep, until you can just wait by the bed untils she's asleep.
The final stages, once she'll tolerate falling asleep in the cot herself with you waiting next to the cot, is the process of tiny changes to get you out of the room.