Unfortunately there's no such thing as "turn by turn" guides to NPCs. some have a regular behavior, but their moves will always depend on their cards (which are not always the same ones), your cards, and your moves. So each battle can be different, and the variations are too many to even try calculate turn-by-turn strategies.

I recommend you take on at least one combat class to 50 if you really intend to get most of the best cards. Some only drop from duties, and each card matters, as the amount you own works on your expansion for the deck (you need to own 30 cards before you can use multiple 2-stars, and 60 cards before you can use multiple 3-stars, etc.). So every single card matters. If you start with the mindset to not bother with the duty-specific cards, you will soon find your Triple Triad path come to an end.

Anyroad, my advice is first of to use this site:

http://ffxivtriad.com/cards

Start by collecting the weakest cards and go up. Once you have 30+ cards, and own the following:

Scarface Bugaal Ja
Frixio
Ixal
Memeroon
Mutamix Bubblypots

Get these, and you'll be able to go farm the Indolent Imperial for MGP. Spend those MGP on Gold card packs till you have all 8 of them. I also recommend participating to every tournament (even if you just fight vs Jonas of the Three Spades, he's the easiest tournament NPC), you should still net enough wins to receive 11000+ MGP reward and 2-3 platinum cards at the end of the tournament.