For me, the fun way to play it is to stick to roles. If you need to, use a guide to figure out where everything you need is and build the class you want to make, I say go for it. The major area of contention is the upper board. The best way to go about this is be flexible and let everyone learn every accessory, but pick and choose your augments. This will allow your characters to actually gain a real statistical difference from each other. In my current file, I've only been giving my warrior style characters physical augments and mages magic augments and you can really see the difference when you play with classes with overlay. So for instance, I have Basch as a Paladin, but since I never bothered giving him summons and only a measly two magic type augments the difference between his White Magic and Penelo as my white mage with all the magic augments and equipment, is quite remarkable. Her magic is leaps and bound better than poor Basch, so this keeps Basch as what a Knight/Paladin should be, a decent healer but not one I can rely on for major healing. So for you, who needs a little structure, I would suggest not filling out the License Board. Only take what you need and continue on. I think too many people treat the License Board like the Sphere Grid, when you should really be looking at it more like the Materia, Junction system, or even job class system.

Experiment with all of the equipment. You would be very surprised how the right combination of gear can have some dramatic and interesting effects in this game. Seriously. my Balthier ended up becoming a cross between a FFTactics Chemist (using guns of course) and an FFTA2 Ranger (using items for devastating effect thanks to a certain accessory) and it's pretty amusing to say the least. I find the one-handed swords are simply the most basic weapon, but the other weapon types end up offering more in the long run. Staffs and rods can make or break a mage character. Also, don't bother with the Zodiac Spear. It's fine if you feel the need to pick it up for OCD sake, but honestly, there are actual better weapons in the game. The Masemune is actually a better DD weapon in the long run, so don't be fooled into thinking you need this weapon cause it is the "Ultimate weapon". The whole thing is similar to the Illumina vs. Atma Weapon debate in VI. Technically the Illumina is the better weapon overall, but the Atma Weapon is actually the better damage dealing weapon with the right set-up.

As for Gambits, once again, build gambits to the characters strengths of their "roles" not gambits for every contingency. If you were playing Tactics with your own party build, you wouldn't necessarily have every unit capable of being efficient healers with magic and item commands would you? Same goes here. Generally for me, Items are something I regulate to myself, I never let the game control that aspect of combat, so I never have HP<30% use Potion, the Gambits are here to make the game manageable and strategy based, not to be self-sufficient. no Skynet on my watch. Gambits are ultimately tricky cause it really depends on the player. Usually you need to feel out what is comfortable for you which may mean either empowering or de-powering the A.I. or even flat out ignoring Gambits all together. This should be left up to you because the game makes Gambits completely optional, which is why I'll never understand why people hate on them.

Also, do the Mark Hunts as they come along and the optional quests. Some of it has some story relevance and others are shout outs to the FFTactics franchise. They are also the more challenging aspect of the game and as long as you do them as they appear and don't grind, you will find they are actually quite fun and require knowing the game mechanics well in order to win with little anguish. They give great loot as well. The only downside is that they make the end part of the game rather easy, so you may wish to hold off a bit once you reach Archades, if you want to make the last part of the game a bit more challenging. Though I highly recommend not fighting Yiazmat unless you are going for a completionist file. That fight is just awful...