If you keep failing to defeat early raiders, the try and
keep your town garrisoned, for a greater success.

Checking your Diplomatic Relations Chart, on regular 
occasions, will help you knwo where your battling
empires are, and enable you not to get involved in ana 
alliance that will se you get several automatic enemies.

Only build military units to a size your economy can 
handle, unless you mass them for a quick strike against 
some wealthy opponent.