I grabbed the two rebel towns Campus Chatti and the other to the south west of your capital. Move fast to them, the garrisons are easy to beat with your starting general and couple of spearmen and a couple of hunters.

I went for stables in my capital to give me simple (i.e. weak as paper) cavalry to put in my armies. I think this was a good move as latter on I did a lot of defending and a couple of cav units give you alot of flexibility on the field.

While Chatti gives you a nicer looking eastern border and some breathing space, the other rebel town can build a port and I think that is far more important for what the Saxons will be getting up to. But get them both anyway and you have a more stable "empire". They are an excellent buffer to your capital.

I managed to get alliances with everyone around straight off the bat, Burgundii, franks, WRE etc but the WRE backstabbed me really early, about a turn after I beat them to the rebel town South West of my capital in fact.

But if you are going to be at war with them anyway, I feel better if they start it.

Hunters and basic spearmen will help you hold onto your three towns from the WRE at the start, if you get too many fancy units for defence you will be in trouble trying to repair them between attacks.

You start with 3 boats in the North Sea and if Pirates dont get them first (!), build two strongish, mixed armies (not necessarily maxed!) and go "invent" the Romano British! You start with alot of money and I used this to fund the expitionary force. I didnt have to build more boats to do this but in retrospect that was playing with fire! With a mix army, use your spearmen to hold and work around to the flanks with cav or whatever you have available. Units hold alot longer and as such the battles a more enjoyable.

I had a terrible time with the Vandals later (this was my first time) but hey, wheres the fun if its too easy right!