Only one missable in the game (if you don't include missing out on max stats). When you get to the Steppe for the first time and fight the story monster there, you'll get one of those pick-an-option things. Pick the one that sounds most rediculous for one adornment (recommended) or another option for another. Apparently there is a work-around to get both adornments. Anyway, adornments give no function other than adorning.
Also, there are a few unique monsters (and a 3-of-a-kind one too). Mess them up and you can't replace them. Mostly, they are the ones in the "Cheats" section.
As for the stats, the guides in the FAQ section can help optimize your main characters.
Furthermore, at Bresha ruins you'll have 2 choices of what area to go to next. Sunlith is the more difficult route and I recommend coming back to that later.
When raising monsters, try to use materials with potent in the name. They are common drops. Use only "power" items if a monster has the "strong" attribute. Speaking of attributes, try only using monsters with early-peaker (preferably) or well-grown attributes.
Other than that, things are pretty straightforward. Develop your own strategies. Eg some people like using sentinals, others prefer medics. Some like synergists, others prefer sabateurs. search the boards for recommended monsters (eg flanitor, cloudburst, behemoth, etc)
The Crystarium is very different, so I really suggest to follow the guide at least once. I've done the game a few times and followed the Crystarium and I still quite haven't figured out how to do it right without it.
Adornments are not very great... they're nice little aditions, but not very good. The live triggers have some funny options and give some funny scenes, but overall you can skip them and won't miss out too much.
"If sense were common, everyone would have it." The gamer who dislikes FF VII, OoT and similar and isn't afraid to admit it
And which walkthrough to use--Split's or Jonathan's?
I used Jonathan's and don't remember any issues
like the other guy said there aren't really any missables, but there are a couple of areas that are (imo) a pain-in-the-ass to go back through if things aren't done the best way the first time and you're going for platinum
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