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My butcher has good dry aged beef, so I dont do it at home. I also dont bother with the terracotta thing. Tried it once, but I find that my oven is good enough that the benefit is minimal.
For potatos I used a peeled starchy fluffy spud. While they are parboiling I heat up a roasting pan in the oven with a bit of goose or duck fat. When the potatos are ready strain them, give a bit of a shake, then toss them with the hot fat in the roasting pan. Throw the pan in a hot oven and give them a toss every once in a while until they are a nice toasty brown.
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