Hey, I'm a pretty experienced single-player, and I'm looking to start getting into ICO.
Be prepared for a bruising... like all of us when starting MP initially.
I play most of the time as TEC. I build an Akkan, swarms of Cobalts, and expand. Once I've gotten as far as I can without serious resistance, I build Argonevs, phase inhibitors, and mines. I turtle up and build a huge economy, while researching and maxing my fleet supply. Mostly Pecherons, Kodiaks, and LRMs (I generally keep most of my fighters around my fleet as a CSP, so I ignore Gardas), and I build at least one Sova, one Marza, and supporting Hoshikos.
Once I finish my fleet, I break through the AI's defenses, roll over its lightly defended systems, and faceroll to victory.
Now, I'm positive that I'll get my ass handed to me playing against real people, and I know there's gonna be a pretty steep learning curve. But is there any wisdom that more experienced players are willing to impart?
Sure.
Let's start from the beginning. An Akkan is a good start for a reasonably spacious map, but Cobalts are probably not a very good idea. Usually, you want to advance towards your enemy as fast as possible, and hopefully grab a choke point so that you can build 2 frigate factories there so you can prepare to pump out units in anticipation of the first real fleet battle. Again: advance your capital ship as fast as possible. This means, often, that you should colonize as soon as you have the resources to get the planet out of negative income (and after the siege frigates are dead), so that your capital ship can move on to the next gravity well ASAP. Don't even stop to kill the rest of the militia! Instead, build a turret. A single turret can take care of almost any number of enemy light frigates and flak frigates.
But to build a turret you need to be able to colonize first, and to colonize, you need to first kill the siege frigates. Getting rid of the neutral siege frigates will be the main barrier to your expansion. Now, the weapons that Cobalts have do only 75% damage to the enemy siege frigates, due to the siege frigates' light armor. There's a much better early-game unit that can be used for clearing out siege frigates: scouts! Although scouts don't usually do much damage, if you have 3 or more of them, they can take down a siege frigate reasonably quickly. This is because their weapons have a 200% damage modifier against siege frigates! For what you're trying to accomplish (kill siege frigates), scouts are much more cost effective than cobalts.
So: Build a colony cap, then build scouts, and send the scouts with your capital ship to kill siege frigates. Colonize the planet as soon as you can, build a turret, and move your fleet to the next planet ASAP.
Using this sort of fast-initial-expansion strategy, I can usually get 5 or 6 planets by 10 minutes into the game. It has won me a few games against significantly more experienced players. If you want to be decent, you have to know how to expand quickly.
When playing against humans, you should almost always be relying on your fleet rather than static defenses such as mines and starbases, which can (and will) often be easily evaded. Do you know about the damage vs armor type chart? You'll probably want to know it like the back of your hand. Also, try not to research anything except if it's absolutely essential, or if you have a bunch of extra funds. If you're TEC, a key to winning is to build multiple trade ports as soon as possible (less than 12 minutes in). The income will allow you to spam more units.
If you want to play a game or something, feel free to PM me. Honestly, I haven't played that many MP games myself, but I'm decent and can give tips.