General stuff
1. Have a diverse army. In BZ2, a Rattler turret was 40 while a Gun Tower costed 50. In BS, it's around 12 to 45. Try to group a good number of different types of units to defend/offend. But be sure to watch out for the units made strictly for human players (like the Interceptor)
2. Use air vehicles for flanking your opponents while they are engaged with your main battle forces. Their heat-seeking weaponry is pretty damaging, but can easily hit your own forces. So it is best to send them into battle from another direction.
3. Plan out your upgrades. Upgrading extractors is risky business, you'll need to figure out what kind of army you want before you upgrade. One upgraded extractor (UE) will give you all the "Level 1" units at a fast rate.. turrets, scouts, razors, sentinels, sentries. 2 UEs will give you missile scouts and standard tanks. 3 UEs will let you pump out modified tanks. But upgrading will definately make advanced technology harder to get at since Scrap Total is cut down with each additional upgrade. So a player who wants to "tank rush" may have to deal with an enemy that has more hi-tech units.
You'll need at least 4 Es to effectively upgrade to 3 UEs.
4. Have plenty of scouts, and try to play as often as possible from the Satellite view. You'll want to find out where your enemy has poorly defended his pools, or even his base, and want to strike at that area immediately. Putting a scout within your strike groups is a good idea too, because they can pick up the visual data and transmit it back to the Satellite. You can better prioritize your battle tactics this way!
I've played too many games where I can just leave pools undefended and still win the game because the enemy tries to win through combat attrition.. they just keep trying their luck in battle, hoping to kill more than I do. If they had known how poorly I was defending my Es, they could have made things much harder on me...
5. "Follow me" and "hold" get a faster response out of your AI units than the other commands do. "Hold" will make all of your units scan their attack ranges for enemies to engage.
6. Setup waypoints in an efficient manner. I like to use a clockwise pattern of waypoints. Waypoints at your base, your enemy's base, at all the pools. Great for quick movement of units.
ISDF stuff
1. The Mortar Bike is great for taking out poorly defended extractors, but not much else. They outrange turrets and should be told to "Hold" around 200m from their target.
2. The Interceptor has MITS mines, but only the player can effectively use them. This is a great way to halt larger enemy units... but make sure you don't blow up the MITS mine while firing on the victim
3. the Uber Death Cannon is "the very best there is." The final phase of the MAG cannon when in Assault mode (when it's equipped on an Assault Tank). It does 8000 damage and has a range of 230-250m or so.. perfect for destroying Heavy Gun Towers (one shot!). Drains you completely though.The UDC round travels at 30m/sec, and has 0 damage from the blast radius. So if you see a UDC coming at YOUR base, JUMP into it and take one for the team! :) You'll save a building from death :P If you can't make the jump in your tank, try jetpacking into it as a pilot...
4. FAF-equipped Missile Scouts is the best way to go for these vehicles.
Scion stuff
1. Gauss for your Guardians is VERY important! Be sure to get these pronto. But without Spire support or something like that, they will be torn to shreds by long-range weps.
2. Archers shoot and fly much faster than they used to. Pretty cheap too. For anti-air defense, the Archer gets CHEAPER (Popper-equipped).
3. When shooting M-lock 2 missiles at something, try aiming upwards before releasing the load.
4. Titans standard can be devastating, even under AI control. The Sonic Blast rounds can deflect incoming enemy rounds easily. But you should probably upgrade the Titan to Arc Cannon if you're planning on fighting in large battles... cuz the Titan can only deflect rounsd from one enemy at a time :P