Here is a tactical rundown of what I see from your list.
farseer: guide, singin spear. 78 pts
Everything you have is BS=4 (Except the Guardians - more on these later) and/or small units, so I think that you should go for Doom instead of Guide as it will help more of your army at 1 time and it really assists with the DA, Guardians, Frag EML's, and the Hawks... where Guide can only help a singel entity per turn.
5 fire dragons: exarch DBF and crack shot. 97 pts
I love this unit.... Versatile and you will be able to squeeze them into a Falcon when your list expands (if you take that route)... Awesome... just use the cover well to get them on site, and don't let them get assaulted.
8 dire avengers: exarch twin cat and bladestorm. 128 pts
Another good unit.... solid choice tof almost any scenerio. I do caution on the use of Bladestorm (Doom would help here again) and try notto get them Tarpitted as their shooting is often their best attribute.
10 guardians: shuri cannon. 85 pts
Make sure these guys cover your Fire Dragons and/or the Avengers.... they are more expendable than the Aspect Warriors and don't disregard their Catipults... they can do well if you try to use their shooting before they get into CC. A bigger squad would help as their low LD will mkae them suseptable to running.
5 swoopin hawks: exarch sun-gun skyleap. 147 pts
Another Minimal Squad... not a good thing as I see it.... If it had the Intercept it might be able to score an early tank; but then the Sun-gun wouldn't really be required as the squad would probably get vapourized shortly there after. I like Hawks, and I can use them to great effect; but, I am used to playing very carefully and having a lot of scarier things on the table that are so fast that the opponent has no time to consider kiling my Hawks.... I would llike to see how you use these guys; but adding intercept and adding more Hawks would not be a bad thing if you asked me.
warwalker: 2 x EML. 70pts
warwalker: 2 x EML. 70pts
warwalker: 2 x EML. 70pts
I actually don't have a problem with these units as the long range of the EML will give them a better survival ratio. The fact that they are Versatile is good as well. You may want to configure them with duel Scatterlasers if you think your enemy will have a lot of light vehicles; but, even with EML's the odds are good that you can drop soemthing, and for 70 pts, anything in the bag will get you their point back.
OK,,,, Now onto how to use it...
First, lets say that you took Doom instead of Guide, dropped the Sun-gun and added Intercept, Leaving you few points to spare still; but not a big deal. I would Set-up with the Walkers spread out a bit; but close enough to actually mass there fire if required and with a decent LOS ontot he battlefield while using cover to block some return fire (Don't forget they may have a Scout move to "Decieve" the enemy a little). Then drop all the infantry into/close to/behind cover but pretty well all together as it will be the Rolling Hammer of the Army. Finally the Hawks should go as close to an enemy vehicle as possible; but behind cover (Well Hidden). Give your opponent first turn unless he is a Super Fast shooty army (DE, Saim-Hann, RavenWing, etc) this way he will probably waste most of hte first turn trying to get LOS onto your squads....On your first turn, you can now move the Hawks, and fllet them to gain either an assault on a vehicle, or better possioning to assault next turn, if their in trouble - Skyleap out of there. The Rolling Hammer starts to advance, and if they have no targets, then they should Fleet to gain another advantagous position on the table. The Walkers pick the most dangerous thing in his army, move out to gain LOS (being careful to not overexpose themselves, and pound the crap out of his priority target; they make sure its useless. After that on his turn 2, if he hasn'e assaulted into you, you try to gain the round of shooting before assauting with your Rolling Hammer, use the Hawks to Drop that Vehicle or Mobile Snipe and grab objectives, and keep the Walkers moving and shooting from as far away as possible.
I think you stand a decnet chance against most all comers lists, but, experience will be your best tutor.
Cheers and Happy Gaming.