Tales of Berseria

• Any item with a bag for an icon is there to be sold to merchants. There's no reason to hang on to them.

• At a certain point in the game you'll get the ability to fight two enemies at once in the field. When both are close to you, a black aura will be shown around them, and engaging at this point will start a "Dangerous Battle". In my playthrough on Normal difficulty this gets me six times more experience per fight than fighting the enemies one at a time, which changes battles from a pointless waste of time into a great way to farm EXP and grade.

• Overall it's actually a very friendly game for missables. The in-game map has friendly green markers which point out interesting things like sidequests and voiced NPC conversations.

• I forget if the "sleep at inn" skits are highlighted in this way as well, though I think they may be. There's one of those in the snowy city early on when you've just got Velvet and Rokurou, which gives you a new outfit for Rokurou.

• Skits in general presumably have cutoffs, although in the postgame there's a skit viewer that lets you unlock them so that's not a permanent issue.

• Probably the easiest missable is seeing all the varieties of boss mystic artes, for the purposes of the one trophy/achievement for seeing all mystic artes. If you don't care about that, don't worry about it.

• If you want to be extra completionist - although honestly skill-learning isn't that crucial - don't sell or dismantle your last copy of a piece of equipment until all party members who can use it, have learned its skill. There are six party members in total. If you don't have them all yet and want to teach those skills to them, hold on to them.

• You can do everything and unlock everything at whatever difficulty level you please, and change difficulty on the fly throughout the game.

• Do those "code red hunts". For the late-game one that seems like you just can't hurt it, either use reflect-damage techniques available at higher difficulty levels, or set the game to the absolute lowest difficulty level; the rest you should be able to handle on your own at whatever difficulty you prefer. The game has a key-item system called potentites, where various plot points (often bosses) and strong enemies will give you one. These have a variety of passive effects, most of which are at least somewhat useful (though some won't be applicable below a given difficulty level). There are a lot of code red hunts, so consequently there are a lot of potentites from code red hunts.

• There are rare herbs that can be used to permanently boost stats. The game mentions that they will regrow over time, but they actually can't regrow until you've pretty much beaten the game, so don't bother checking on them once you've picked them.

• Don't feel like you need to go out of your way to collect Katz souls. They are pretty much only useful for cosmetics and they respawn whenever you leave an area. If you can't open them yet still try as that will put it on your map.

• Cooking is a full heal in this game and it's super cheap, so you should set it to auto-cook after every battle.

• Keep gear with extra skill gain on it, as once you've learned the skill you can keep it equipped fit double benefit. Helps power through skill learning.