My starting strategy generally goes like this:
On the first turn, my starting army usually sits in my home province and I recruit troops to add to it in preparation for sending it out on turn 2. Some nations have really strong starter armies and may be safe to launch attacks with, others are really weak and risky to send out on turn 1. What I recruit also depends on the nation. If the nation lacks holy-3 priests, I usually prophetize my starting commander on the first turn as well. Otherwise, I sometimes go without a prophet until I recruit an H3, since prophetizing an H3 results in an H4 prophet.
After turn 1 I try to expand as fast as possible, which means raising new armies to increase my expansion rate (and recruiting reinforcements if I'm losing troops, and sending them to the army instead of sending the army back), watching battles and then adjusting my army formation, composition, and orders to try to optimize their performance, capturing farmlands to increase my income to increase my ability to build armies, building palisades in places where they can get lots of resources (e.g. adjacent to multiple forest and/or mountain provinces) to increase my army building rate, and recruiting and sending out scouts to find out where the other nations are (generally recruiting them every turn on repeat from one or two provinces).
But I also try to balance that with increasing my research rate by recruiting mages as often as possible from as many forts/palisades as possible, with site-searching once I have a decent research rate, and with scout-recruitment (I prefer recruiting non-fort scouts, if possible).
Once I start running into other players, my army composition tends to change - or I build border forts - since in EA and MA you can roll over indies with a fairly weak army, and other players' armies can be considerably tougher, especially if your troops are weak and theirs are badass (so you rely later on magic or summons, or blessed troops that you recruit slowly over a large number of turns).
Diplomacy also comes into play in most multiplayer games I've played (generally as early as possible). You don't want to end up being the guy that everyone gangs up on - unless you can actually take them all on at once.