The Legend of Heroes: Trails in the Sky

If you want the ultimate weapon you're gonna need to find 10 collectibles that you should absolutely look up where they are because if you don't you will not find them. Additionally, there is a minor save transfer bonus for getting maximum BP that similarly requires a guide.

Nearly everything you need to know is in the Bracer Notebook: What every spell in the game does and what quartz combinations unlock them, what effect each individual quartz has, the various rewards for each Bracer Guild rank you achieve, etc.

Pretty much every sidequest is found on the billboard in the Guild, but there's around three hidden sidequests scattered throughout the game. If you want to get max Bracer Points, you'll want to use a guide. Note that all that max BP does is give you a bonus in the sequel if you transfer your data, you get the best reward for collecting BP much earlier. So if you're not much of a completionist, don't bother. Also sidequests can expire pretty quickly, so if you want to do one, do it when it opens.

Time magic/quartz are really good, and so I'd default to throwing them on a character with room. Hell's Gate and White Gehanna do lots of damage, and have a good chance of causing faint, incapacitating an enemy for a while. The quartz also have useful effects (Cast time Up, Speed Up, stuff like that.)

If you really want to cheese things, get as many people as you can to have Earth Wall. Everyone it's used on will take no damage from the next attack that hits them, meaning you can basically turtle your way through everything. Combine this with quartz to increase the effective radius of spells, and to reduce EP usage to break things even further.

In Chapters 1 and 2, make sure you visit the Amberl Tower and the Sappherl Tower respectively. They seem like places the plot would bring you to eventually, but they're actually just bonus areas with treasure to pilfer. (And in the former case, the location of one of the hidden sidequests I was talking about.)

When you lose a fight, you'll be given the option to retry. If you do this, the enemy will become slightly weaker the next time you fight it. There's an option buried in the menu to change this if this doesn't appeal to you. (If you don't retry, you'll need to reload a save.)

You'll notice that party members tend to come and go fairly often. Don't worry about them stealing your stuff - they'll leave everything, including stuff they brought (which you can freely sell for profit.)

Every once a while, go the general store and buy the new issue of the Liberl News. They're normally fairly interesting.

Don't fight too many generic encounters. Between the chests guarded by monsters, as well as scripted encounters and bounties for the guild, they're not really that necessary for staying leveled. This is more applicable if you're doing the majority of the sidequests, however. You might need the extra EXP if you're doing a more bare-bones run.

It's not actually that long. If you know what you're doing, you can do a completionist playthrough in 40 hours without too much trouble.

If you're gonna do side-jobs, do them all before doing the plot quest. Some of them have very small windows to complete them in.

Look at every chest you open after you've taken the treasure from it, I can't stress how important this is. You'll figure out why after a few of them

Keep Cast and Action on everyone, and as up-to-date as possible. This will negate faster enemies' high speeds, trivialize slower enemies, and make bosses only get two turns in a row instead of three or four.

Time and Wind are pretty much the best offensive elements in the game, so definitely gear for those. See the magic list in the guidebook menu, it'll list the quartz combinations necessary to learn spells. Time's White Gehenna and Wind's two strongest attacks feature the most important tactical feature a spell can have: being able to center the spell on a specific tile instead of being forced to center their area of effect on an enemy like most spells. Magic has 100% accuracy, which is important when you don't want to frustratingly miss an enemy with single-digit HP remaining and some stupidly powerful spell in its repertoire.

Earthquake is also a powerful spell, but you won't be able to make the necessary quartz loadout for it until pretty much the end of the game.

The Earth Wall spells are kind of brokenly powerful since they fully negate the next attack a character takes, and they're super easy to get, but you won't really get enough MP to cast them all the time until late in the game.

Some enemies explode when they die and do huge damage. Sometimes, the Information quartz will tell you this in their status narration. Sometimes, you just get exploded on and die. Such is life.

Shining Poms (this games version of Metal Slime, worth a lot of loot and xp + an achievement for killing one in each chapter) are basically only killable via S-Breaks.

Early in the game, you will revisit the first tower. On your second trip in, explore thoroughly until you find an item called Potluck in a Shell. Do not leave the tower until you find this item. It's a very cheap item that fixes K.O. status, which will free up a lot of money.