When I make things like this I leave a long tail, I use that tail and a yarn needle to sew the pieces to each other. I do a running stitch to tack it down. Here is a video of what I am talking about http://youtu.be/EG_0Jmx2_RQ?t=1m59s
It will naturally be a little off. It is handmade not machine made. If you block it, it will more likely straighten out. I never turn when I make my giant grannies A quick wash in the machine and air dried takes care of it.
I saw the blanket on pinterest ( originally with no pattern in the link) and knew I had seen the stitch in my crochet stitch bible. My bible has gone missing so I don't know the name of the stitch, but never fear the original blogger put a tutorial on the stitch on her blog. the heart is also from her.
the only problem I had was i feel it is off balanced since the top is on the diagonal and the bottom has a straight edge because of the chain. But I think not having a border is pretty nice too. Enjoy!