Knitting a baby blanket

I am a new knitter. I saw a beautiful baby blanket on the TV show Knit & Crochet. It took me 3 weeks to knit this blanket. It is beautiful, but it is crooked. What should I do to straighten it out?

What’s the fiber? If it’s blockable you might be able to stretch one part to square it off. If it’s acrylic, probably not. Sounds like you may have added stitches as you went along.