Post stuff Tips,Tactics and Tricks that would help on the battlefield.

Equip the artillery strike on your scouts, infiltrate them in and blast the crap outta the enemy. Jump assault marines in to clean up, natch.

Jump Assault marins are fucking awesome

Jump assault marines into the middle of enemies,then move your devastator squad into cover and have them open fire.Then rush with your force commander and Cyrus/Tarkus.

Also, when playing as Eldar, Warp spiders are beastly, and wraithlords are your friends.

the Dredknott like all others cant shoot through towers but the knockdown spray will. put him in positions, spray, knock everyone down and let everyone else mombo in/through,over the wall.
in deffence dont deploy mines, wate till ther all massed up and them plop in in the middle. they wont scatter like nads or the backpack bombs.
dropping air strikes on people, 1) time it when the big guy first walks on the screen, they always walk in a straight line,  target wer ther going to be in 3 seconds, will take a decent chunck out of em. 2) bum rush em with the mellee guys, tangle em up, target air strike right in the middle of the cluster then use your force commander guy to employ the golden globe thing of no damage, no friendlies get hurt. 
combo kill medium level with FC. jump, knock em down, use the charge, knock em down, then split ther head with the mallot. takes about 3 seconds

If you are rolling a 3v3 team, the best thing to do is roll an all Tyranid team.  Make sure two of you roll Hive Tyrant Heroes, while the third rolls Tunneler.  Kick the shit out of the early units together to level up quickly, then work on some upgrades on them down the line.  Hive Tyrants work well when they have their increased melee power, as well as the skill that lets them use their energy instead of their health when being attacked.

Yea Tyranids and Ork's are rushers, and the Eldar and Space Marines are....tricky

I've recently gotten really into this game so thought I might revive it and post.

I've found the most effective way to deal with most missions.

Force Commander | Plasma Pistol/Chainsword or Two Handed Thunder Hammer
Tarkus/Tactical Squad | Bolter
Avitus/Devastator Squad | Heavy Bolter
Thaddeus/Assault Marines | Two Handed Thunder Hammer or Terminator Armor/Thunder Hammer & Storm Shield

-Setup Avitus
-Use Tarkus's "Taunt" Ability and lure them into Avitus' firing range
-Engage Avitus' "Focus Fire" Ability to supress the enemy
-"Assault Jump" or "Teleport" (dependant on whether Terminator Armor is equipped) into enemies with Thaddeus
-Use Force Commander's "Battle Cry" Ability to make troops immune to knockback.

Then if you have the following items, "Signum" & "Rosarius", continue with this technique.

-Select "Artillery Strike" (Signum) and direct it where your Assault Marines and Force Commander are fighting the enemy
-Just as "Artillery Strike" is about to fall, enable "Blessing of Fortitude" (Rosarius) which will make your troops Invulnerable for a set amount of time.
-Then once "Artillery Strike" is complete, "Battle Cry" again and use "Stimulus Kit" to heal all squads.