I don't know the Pete Collings tutorial nor your version of Photoshop, but if you can, one of your best bets for enlargement today is to use Photoshop CC's Image - Image Size feature, and choose the Preserve Details (enlargement) method.
Plus Smart Sharpen does a nice job of crisping images up after upsampling.
You need to consider the remote possibility that we won't all know who Pete Collins is, or how he recommends upresing images in in Photoshop, so a link would have got round that nicely.
However, a quick Google reveals Pete to be one of the Kelby TV Photoshop Guys, and the only reference to Pete and enlarging was this article from the official CC help pages.
If this is what you were referring to, then yes, this is currently the class leading way to upres an image in Photoshop.
Regarding the second part of your question, you'll need to be clear on what you mean by "Cropping to enlarge".