Now, I've never steeked before so this scared the hell out of me, and I wasn' exactly looking forward to it. I mean, who in their right senses would make holes into their knitting, especially something that took me almost 2 months to finish ? But it had to be done, so I gathered my courage and decided to go for it. I followed Kate's wonderful tutorial which really explains everything beautifully.
I decided to start with the collar, since it was the smallest steek and therefore less chances of getting it wrong. I first made my crochet reinforcements using a sock yarn that was similar to the main color of my cardigan, as you can see here:
And voilá ... it actually works !