Well, first off, I never really liked Fleet Operations (don't kick me out~~~! Now l love it!! ) It was like Armada 2, except its a whole lot laggy and models look weird.. lol As I played more and more, I realized that there is great strategy in this mod, and I would like to share some of mine.
I use each ship for a specific use, and I beleive that it seemed to be really effective. Also, I use this strategy so that I have minimal casualties and losses on my side...

Venture: Like I mentioned in some other post, I use it as attack fighters, primarily to draw more fire away from the main attacking ships. It is best if 1/4 of the entire fleet is Ventures. I think Venture is not suitable for scouting since it is too weak even though it has a wide sensor range

Saber: I use it as Light assault ships because if its small size, high maneuvreability, and minimal firepower. I use it as taking out pesky Bird of Preys and sometimes bigger Rheinn classes, but can handle much more larger ships in more numbers, (Galaxy, Warbird etc)

Monsoon: Well, I think it is my main attack ship that destroys large ships. You might wonder why I use it for destroying large ships, but I destroyed a Negh'Var with only 2 Monsoons.  

Intrepid: With Photon torpedoes and Tricobalt Torps as a special weapon, I use it to take on all stations, ranging from sensor satilites to Starbases

Akira: I use this ship to take out its own size ships, (Rheinn, Sphere, K'Tinga, etc)

Caneveral: I use this as scout ships , beleive it or not. Like I said, Ventures are way too weak for scouting, what if you meet 2 Warbirds? Venture doesn't stand a chance, but the Caneveral can fight back, and survive until it reaches the base.

Galaxy: Another ship to attack stations, but I also use it to take out large ships of its size.

Nebula: Because of its pulse Phaser, I use it to take out small ships, like Saber, BoP, K'Vort etc.

Streamrunner: I don't really use this ship, but If I am forced to, I would put it on a base, so it will attack incoming targets in long range when my defense platforms are out of range

Descent: I also don't use this one very often, because it costs 3 credits. To me its not a recommended ship.  

Remoore: Well, I research the special weapon for this ship, and I send them with Galaxies and Nebulas.

Excelsior II: For this, I usually use it for defense. Seriously, it is a great defense ship, with 4 quantum torpeodes firing at a time rapidly, it is really good at defending the base. I would recommend that you put at least 4 on your base. You could also send it with a main fleet, but I don't usually do that unless I go for a last and final assault

Defiant: I don't use that much either, because of its high costs and painfully long recharging speed!!!!!!!!!!

Sovereign: Also, because of its quantum torpedoes, I use it for defense, and when going for a final assault, I dispatch all Sovereign s I have~~



Well, I hope I helped...  
 

nice discription of the Fed-Fleet

i have also some personal notes to the ships

Venture:

i use venture for scouting in the early game, later i also switch to Canevera


Saber:

oh, i love this ship. it is cheap ,fast and has longrange phasers. I often use it combinded with the Excelsior II as fire support for my fleet


Monsoon:

in 80 % of all games i skip this ship. But when you play against an Klingon, Noxter, Romulan it offers a great firepower to kill the the little ships ot your enemy


Intrepid:

a great ship, it's the first Fedship that have Torpedos, so you can use it against buildings or great ships, but also i often have no use for that ship, because it have less hitpoints compared to the akira or galaxy


Akira:

Ok, thats one ot best cruisers in the game ( for me ;-) ) . Combind with the galaxy you have a great assault fleet. The best is the Akiras point defence system, so torpedos have no chance to damage your fleet.


Caneveral:

Good scout ship ( probe), if you have to much tritanium , you can use it as replacement for the saber as longrange support


Galaxy:

A vital ship for me,it has only crew- and creditcosts, so i use it to skip the time until i can build Sovereign, because it plays same role as the Sovereign


Nebula:

i only use it, if i know that my opponent will use small ships


Steamrunner:

Good option for firesupport, i often combine it with the Excelsior II


Descent:

You need something bigger than as sov? Here is it, later in the game i disassamble my galaxies and use Descents instead


Remoore:

Yep, with ecm it is a good support ship. Klingon, Borgs and Romulans will hate this Ship


Excelsior II:

Need for Longrange torpeos and a medium ship killer? Here is it, a very vital ship for me. I use it to backup my sovereigns and galaxies. so my enemy get overwhelmed by torpedos and he can say goodbye to his big ships and stations.


Defiant:

Small Ship Killer, it takes a BoP with one shoot out


Sovereign:

That the King ot the Federation.  Whit it's first shoot it makes 64 Damge (4 Quantentorpedoburst) , only with torpedos.  a other great thing it her Distortion Field.
It disables the engines of all enemy ships in range, so that every torpedo , that is fired hit his target


Newton:

!!! use this ship !!! , you can reapair the complet hull of every ship , that is a great advantage in combat

so that my personal notes to the federations ships, i hope you enjoyed it to read

hehe, very interesting to see what playes make of the possibilities delivered by the balancing system you will have to adjust this lists after the release of beta3, there will be many changes to the stats of vessels

my favourit federation vessels are for beta2:
excelsiorII (superior allround vessel)
defiant (do you need some fire power? yay, here i am!)
steamrunner (to crush the large vessels where the defiant is to weak cause of its pulse-type weapons)

I took out a medium romulan in no time with a fleet consisting of these ships:

Canaveral Class: Shoots probes into the enemy base and can fire long range into the base while the fleet enters it, to do damage before the rest of the ships can take over.

Akira Class: Shoots powerfull phaser beams that I mainly use to atack ships and has Point Defence.

Excelsior-II Class: Takes care of everything else using its quantum torpedos to atack stations ships and defence.

LoL, when i need a masive SaD i make more ventures than you could ever imagine and i pwn the map with them weather you be cloaked or just some where on the map you will be found.

For me the Excelsior II is always the most effective vessel.  If my starting venture makes it to the end game then my least effective ship is the Galaxy oddly enough.  I have to try venture classes next time.  See how good they are in numbers.  

Saving and reducing the number of casualties is also esssential. But if I am quite sure that I am gonna take down my enemy in one hit, I build Ventures and I build them a LOT. But I am taking a serious gamble there..

I don't quite understand the fetish with ventures in massed groups, they only deliver 1/3 damage unit per second for 70 dilithium, which means they cost 210 dilithium per damage unit per second. Buy Intrepid (105/28), Saber (115/35), or Monsoon (102/47) instead with your money (in that order). Against small ships saber or monsoon, you know the drill.