Gaul

[Vitellus]

As Gaul, I don't know if there is any other way TO play successfully. You have to act swiftly to eliminate one rival before the others all around you grow powerful enough to pose a threat. For me, it was the Romans, and their swift elimination meant I never had any trouble in Italy (before the damned Hellenic intervention), and the funds from the Italian cities allowed me to hold off the barbarian attacks in the north and the Punics/Iberians in Hispania long enough to gain a decisive advantage. GSC was even more successful, managing a non-aggression pact with Germania that allowed him to eliminate the Britons and secure his rear early on.

[gollum]

Indeed as Gaul, urgent action is required. Basically throwing everything at the Romans and taking them out before they get an Imperial palace (God forbids!).

I remember in the last gaul vanilla campaign i've played there were about 20 sites of "famous battles" scattered all over the Italian pen. - Obelix would have been proud :)

[Alrik]

Ok, I'm tackling this the second time through now. Both been on VH campaign and M battles.
I agree that as Gaul you have to be agressive and fast, you have a huge reign and plenty of borders, but no income. It is a priority thus to Stabalize your situation. what I did was barge north with everything in Alesia and kick the Britts into oblivion, this for two reasons, the first time around I had taken their mainland foothold, but had been required to station a huge garison there for most of the game, something that the gauls really can't afford. Killing the Britts thus leaves your back clear and you can have one army less, it also gives you access to a lot of coast and thus ports, giving you much needed income. So what I did this time, was not even taking a breather, but insantly jumping to Londinium and taking the battle there as a result I killed the last brit general by turn four leaving their last settlement to rebel.

similarly in the south, people say Gaul's territory is divided in two and that it's essential to unify it, but that's only half right, it's actually divided in three. Numantia is left totally surrounded and I read here people advising to garison it properly, again costly and again an army that does nothing, but sitt there waiting for the inevitable, I mean seriously you are in the smack middle of Spain's domain, what's he supposed to do? Ignore you? Don't think so, Empty Numantia and charge Osca, this will relieve the threat on Narbo Martius, if you challange Julii early on both these cities will then be left safe, the Carthinians have too many borders to guard to launch assaults all the way up here.
Continue the assult on Spain, Spain starts small and weak, use that, the sooner you exterminate him the easier time you will have, the issue here is Carthage, but he usually take a few turns to warm up, just like the Germans, before they do you should have Spain and Brittania well on their way to oblivion. With two fronts less you have less forces to waste your money on and ALL of the new territories are costal, which gives you what Gaul needs most, money.
Both times I left Julii alone, because I know he will attack, but it's easier to fight a defansive battle and he stats with a sizable army. While waiting for that I sent the forces around Narbo Martius to take Massilla and Lugdunum before going north to reinforce my German border.
The troops in northern Itally I sent to take the rebel settlements. Mediolanium north to take luvalum, then south again to handle Julii while the city spawns new toops to handle the Roman threat. Patavium going east to take Segestica and Aquincum.

Aquincum here is essential, taking it and walling it up quickly and placing a small garrison of four - five units will halt Dacia, who may linger for a while in your territory, but not attack unless you lessen the garrison, this is great and makes them go to war on the other front.

When Julii begins to move (it will only take a few turns) don't hesitate, just smash the bastard. The Senate might have a big army but it will just sit on the boarder and watch, there's no need to engage them if you don't want to. and if you do, make sure it's a bridge/ford battle. The Brutii though will eventually come up the eastern side of the Itallian pernisulae, they will also come north on the other side of the coast. I took Salona and have been keeping them busy in sieges there. He will at times send ships up as well, but unless one of the armies are allowed to march, then he troops on the boats wont come ashore.

After killing the Brits, Spain and julii, in that order I concentrated on Germany and pushing into North Africa, while getting my cities in Italy on their way to producing foresters. I did the same with Alesia, but by the time I managed to produce the first unit 256 BC My armies pushing east were sieging Lovosice and marching on Vicus Gothi, meaning there was a very long way to the front, so I'm not sure producing the units there was such a good investment.
After finishing up with the germans I with a somewhat strengthened garrison in Aquincum made a simultanious assult on most of Dacias settlements, which meant I killed him off in a couple of turns without having to face all of his forces, which proved lucky because my armies were apparently obsolete by this time, facing chosen archers and such isn't fun with first tier troops. Which made me consider waiting there before taking on Scythia, especially seeing as both Campus Lazyges and Porrolissum are big developed cities, which means you can produce good troops there.
However Scythia apparently didn't like to wait so that I could get forresters to tackle their horrible horse archers and moved in immidiatly and sieged Porrolissum, which now faces three nearly full stacks of Scythian troops. That's where I'm at, taken Rome in Italy, pushing with huge forester armies and slaughtering everything there (apparently I could build awesome temple of the Horse in Rome, so I'm doing that, Gold version of the game, no mods)
Have nearly taken out Numidia in the south, but now Carthage is moving huge stacks into the southern desert. (I'm having trouble making the damn cities there happy, which put a serious dent in my progress.) Trying to gather the rebel killing foresters in Spain and France to make a semi-force to take out Malta and head on to help out in North Africa.
Now is actually the first time I faced any real difficulty, first time I played the Imperial campaign with the Gauls, money was the problem, now getting real troops to the front is it., but then again 43 regions by 250 BC, is ok, with Gauls, right? It's probably about time I stopped blitzing.