Tezeu's strategy!
I play on VH/H.
I read here, I read there. Hmm! What the f...! Let's start and I'll see.
So I analyzed: what position I have on the map, what kind of troops(- and +), Who are my neighbours and which are their strategies ON LONG TERM? But their neighbours? Bla, bla, a lot of questions.
Conclusions:
1. I'm very weak at the beginning.
2. I'm lucky with the position on the map.
3. I have two strong neighbours.
3.1. Germans - strong, at the beginning and most important....very compact position.
3.2 Gauls - strong, lots of armies, very aggresive but TOO LARGE empire and for this reason.....too many enemies.
4. For beeing a really strong faction, I must have a great base of operations on Mediteranean Sea. This will be a point for expand my empire and will help me to take Athens, Corinth, Sparta, the most important cities in the game and also Sicilly.

What I decided.

1. Must important, to ally with Germans. Their are compact and if I get into a war with them, I will be forced to maintain all the time a strong army. This means cost and I will cannot have the posibillity to grow my cities very quick.
2. To ally with everybody is posibly.
3. To ally with Gauls. They will attack anyway after only few years.
4. To take Tara.
5. To expand Londinium quickly to next level.
6. To strengthen my only city from the continent. This will be at the beginning very important.

The facts:

1. I started sending Cwnbar with a Light Chariot, the druids and two warbands to take Tara. My light chariots killed alone almost all troops(!!!) with their arrows.
2. The rest of the troops I disbanded in Londinium.
3. I set all the towns to law taxes.
4. I send the diplomat to ally with Germans and Gauls. After that, I sent him in Italian Peninsula and to the greeks.
5. I made another one and I sent him through Dacia, Scythia and so on.
6. I sent the spy to expand his abilities through Gauls cities.
7. For five turns, I create peasants in the two cities from the island and I disbanded them in Londinium.
8. I made shrines, traders, roads and so on.
9. Gauls attacked me with a blocade at Londinium. This was the point were I started pumping troops. In this moment I had money around 23000.
10. I made two armies. I sent one to take Alessia and to stop only after taking Massilia. The second army, I sent to take Condate and all the cities on that side of the map. In this way, the Gauls are practically finished. Their are cut in two.
11. I moved the capital to Alessia.

In this moment I just "arrived" to Massilia. This will be my new base operations for taking Sicilly and greek-macedonian cities.
Second army is continuing it's campain to take Spain. Osca was taken by Julii and this is creating a little problem but I think I will manage the situation.

I'm sorry for my poor english.
If you have comments, please, tell me!

P.S. The chariots with their arrows are awfull. Nobody can face them.