Shin Megami Tensei IV

Dexterity is the important stat for physical attacks, it applies twice as effectively as strength.

Magic or Physical are both perfectly viable, go with whatever you want. Prioritize Dex for physical, Mag for magic, and drop some points into Agility and Luck regardless.

The first couple serious bosses are the biggest roadblocks in the game. The second can be trivialized by getting a Gremlin in the area before and leveling it a few times, at which point it will evolve into a Raiju and is basically immune to anything the boss can do.

The best way to get demons to join you is to refuse their first request, then cheat, then end talks. It seems silly, but if you bargain with demons honestly, they'll steal your stuff and either leave or attack you an awful lot of the time.

Never neglect your agility (or was it called speed?) and luck as you level up, with more priority to agility since that affects whether your character goes first, or is eating shit. I also think it affects stuff like evasion and hit chance, but don't quote me on that, but overall acting first is important due to the press turn system. Luck affects a bunch of crap if I remember correctly, from recruitment rates, crits and smirk chance, with the smirk status buff being amazing (95% chance of evasion or something like that and a guaranteed crit for your next attack, though it's expended after your next action).

Try to keep each element covered for your group, hitting an enemy weakness or critting them only expends half a turn, while on the same note, hitting an enemy immunity will waste all of your moves and move onto the enemy's turn. On the same note, try to hold onto any demon skill that gives immunity to an element as you get them, they can be incredibly useful.

For your first playthrough you may want to focus on magic, since that will give you the most diverse options for hitting weaknesses.

As soon as you can get Energy Drain, never let it go and try to get it on as many of your demons as possible. It will solve your mp woes and it hits for a decent amount too.

Recruit everything. EVERYTHING. Even if you never use the demon it will still gain exp from fights and new skills so you have more options for fusions.

Never feel bad about making a new demon specifically to counter a boss you're having trouble with. Some of them are real dinks or just are rough if you don't go all out.

There are four different endings. One of them you will need a guide for because it's convoluted bullshit to achieve. Fortunately the game has newgame+ with a bunch of options for what you want to carry over for your next game, letting you rocket right through again if you wanted to.

Don't be afraid to 'talk' to bosses or try to recruit them, it won't waste an action (and can be funny). Though shaking them down for items/money/etc. will (which is also funny).

Money is hard to come by, so be selective about gear upgrades. On that note, if you're going to get any of the three 'grinding' dlcs, the money one is probably the best since then you can always play dressup with your equipment, rather than be incredibly selective (or shake down demons for cash).