I myself play
DoA and guard is one of those matchups that can be great or can be really bad. As always with
DoA a lot depends on the terrain, the mission and who gets the choice of first turn.
If the terrain is denser on one side, deffo go for that for yourself.
DoA hate terrain as it can snipe important characters out of their groups by forcing Dangerous terrain tests. Not only that but if you land in terrain and then want to move you need to take more dangerous tests. Use terrain to your advantage when deploying, guard your flanks with it and watch your opponant struggle to place well.
Other things to note
1) In
KP missions he can't combat squad. This makes his 10 man squads have a larger
DS footprint and therefore more dangerous to land. He'll need more space and you can use this accordingly.
2) If he wins the dice roll he'll most likely take 2nd turn. This lets him minimise your shooting at him. However, there are things you can do about this.
Either reserve yourself (it's nasty for
DoA to have to
DS when there's no target to hit, it makes them sitting ducks for when you come on the board next turn)
Castle up. Leave non-DSable gaps between your units. Put your tanks in the middle, infantry on the outside and make him land awkwardly before shooting him a lot.
Spread out. In
KP games he has to keep his combat squads together. This means he probably has 4-6 squads in total. If you spread your army out across the board (using your 1st and 2nd turn movement) you allow him plenty of landing space, but also lots of targets. Sang priests only give
fnp to those within 6" of them, so if he's only got a two priests and you spread out, a hell of a lot of his guys won't have
fnp. If he has lots of priests or lots of squads (for objective games) this doesn't work so well.
Alternatively. If you win the role you can make him go first or second. If one side has much better terrain for you to defend from, then just go and take it. Let him go second and play as above. Alternatively go second and then hold everything in reserve. With the reroll from reserves a
DoA unit has a 75% chance of doing what the player wants (either turning up or not). However, even with this reroll it's unlikely he'll be able to keep his whole army off the board. If he has the first phase of the second turn then he'll be DSing onto the board without a target, which is very bad for him. If he just brings everything on as normal then they're be badly placed and when you turn up next turn you can drive on far away from his troops and shoot him. Alternatively he can try to keep his troops off the board which on average will force him to put a 25% of his army onto the board. This is just as bad as he has troops unsupported, with no target and ripe for the picking when you come on next turn.
3) If he
DSs then you have lovely gathered up units for you to hit with pie plates.
4) Only Vanguard vets can assault from deep strike. And they are either REALLY expensive, or really quite mediocre.
5) Sang guard are good, but have no invulnerable saves.
6) He rolls for reserves turn 2, not turn 3. Nothing about
BA says they can all come on turn 3.
7) It's always better to charge them than have them charge you.
BA AM are only good on the charge. If you have a blob. Charge them, tie them up and then kill them with weight of attacks. Lasguns won't do as much as denying them mobility but making them kill 40 guardsman to do anything.
8) Pick the priests out in assault
9) Not sure if vet squads with lascannons are a good idea in any list, but I don't play guard so I don't know!
hope that helps