It really all depends on what you’re building the anchors on. Presumably you’re simulating using trees? You would not want to girth hitch through metal bolts as a general practice.

Everything should be about efficient redundancy (I.e. practice the techniques you would want to use in the less ideal circumstances). Slings should be attached to bolts via carabiners (I prefer lockers and those are the general rule of thumb).

If you’re building anchors for bolted anchors and want them to be quick and efficient work on building a quad anchor. Otherwise a double length sling halved with an overhand is my standard.

If you’re building trad anchors the options are way more numerous and I’d say find a well vetted YouTube channel or check out the Petzl ebooks on their website.

What I was seeing in the comment were lots of people saying “good enough.” The idea of good enough during an activity that holds your life and likely someone else’s in the balance should be tossed out. Check out AMGA standards and follow best practices. Comfortable people get cocky and cocky people make mistakes.