Hi Quizeen
I guess, basically, it breaks down into those two broad mtheods, but there can be more to it than that. You can on the one hand shuffle and cut and use that card or fan the cards and pick one that seems to call you. Or if you pay attention to the cards that fall out of the deck, one of those could be the significator. In these cases, it seems to me, you are putting your faith in the deck, and if you get a card that is something like the 6 of cups as the significator, you would have to read that as not necessarily you but perhaps your condition or situation.
I think the type of spread you are using influence how you are using the significator. If it's in a CC for example, the first card may actually go on top of (it covers) the significator.
Choosing a card can be much more elaborate, involving meditating on various cards, or choosing one that fits your personality, looking at all the court cards and then using a process in which you choose the eight of the 16 court cards, then 4 of the eight, then one out of the four.
In the first tarot reading ever done for me, my reader wanted to use a significator. She layed all the cards out in nine more ore less equal rows, and then pointing at various rows, vertical and horizontal, asked me to choose a card. She gathered all the cards of that row up with the chosen card on top, and started making a new row with these small piles. Finaly there was a row of maybe 8 or 10 piles with the chosen cards on top. I chose five, then three, then one. She continutally stacked the piles into a full deck until that one card was on top. That was the significator. At this point I cannot remember whether she shufffled again or not, or whether she decided my energy was present.
Anyway, it still intrigues me. I haven't had a chance to try that method yet, but want to.
So there are different ways to choose. Hope that helps.
Nuncle.