Characters to recruit: Make sure you get Mog around the time you get the airship. There are other optional characters to recruit as well, but you won't be able to get them until much later in the game.
You shouldn't be spending that much money on gil and potions, you should be using magic to heal wherever possible. But that won't be possible too much before you get espers. I also recommend using sleeping bags and tents on the whole. They're typically a cheaper method of healing.
I'm sure there's a Blitz guide on the main site.
Also, there is a point in the game where the party will leave Shadow behind and have a timer to outrun. Do not, under any circumstances, jump to the airship at this point. You need to answer two questions: "No", do not jump to the airship, and then it will ask you again, and you must select "Gotta wait for Shadow". If you do not select "Gotta wait for Shadow", he will die permanently. If you do this, he will show up with five seconds left on the timer and everyone will survive.
@specific items, there's an Atma Weapon in the Cave to the Esper World. Definitely don't pass that up. It's one of the most powerful weapons in the game and it only shows up that once (except in the Advance version).
