In Romani campaigns, I usually conquer the Italian peninsula followed by the islands, going to war with Aedui and Karthadast in the process then hold back and develop my economy as well as a nice little navy and maintaining defensive armies in northern Italy and Sardinia. I would recommend you take an alliance with one of the Gallic tribes to secure your northern frontier, and try to make peace with Aedui. After the Polybian Reforms come, I replace the Camillan units in my armies with polybian ones, and usually set out for Spain to take advantage of the vast mineral wealth there, as well as weaken Carthage. It is my experience that after Carthage loses her Spanish holdings, it is easier to declare a ceasefire (as long as you ahve no land border!). After that Carthage becomes a very valuable trade partner, and usually focuses on penetrating deeper into Africa.

Now in my experience, in Iberia it is not to long before the Lusitani attack you and you are drawn into an Iberian war (very much a nuisance, I recommend conquering the whole peninsula for the mines). By now, a faction from the Balkans (usually Makedonia) has Illyria, and will probably attack Patavium, drawing you into another war. But by now, you should have a very strong economy, military, and even a decent navy, along with strong trading partner in Carthage and secure Alpine borders, so a two-front war shouldn't be a big problem and makes for interesting gameplay.

So basically my recomendation is to pursue war with Carthage until you control all her non-African holdings, fight a defensive war on your northern border if necessary, and expand into Greece when provoked. After that, the opportunites are limitless: I usually like to fight Cartage in her homelands before being sucked into war in Asia Minor with the Grey or Yellow Death. You can decide whether to blitz the world or play a more historical, expand-when-provoked game at this point, but however you do it, I find the Romans still one of the most rewarding and fun factions with limitless replayability.