I tend not to post any videos but my own, but this video on the tulip buttonhole from Interweave knits is not to be missed. If you’ve tried making a decent buttonhole, you’ll see the value in this immediately. It looks like a little trouble, but the result is so worth it.
Watch this video by Berocco on casting on. Watch the long tail cast on closely. Is this how you do it? After scooping the thumb yarn, I have always brought my needle over the top of the index finger yarn (clockwise) and though the thumb loop. In this video the narrator brings her needle under and over the top (counterclockwise) of the index finger yarn. I tried it a few times and think the difference is the way the loop lies on the needle–I think the Berocco way gives the stitch the proper twist. I am still working swatches to see if they look any different.
The Berocco videos, by the way, are terrific. You can get on their mailing list and get notified every time there’s a new one.