Take note of where the oil derricks are on the map
1. build barracks first
2. make bears/dogs send them to oil derricks straight away (just a couple)
3. capture with engineers.
4. defend oil derricks - build base next to them to flank opponents.
Make sure to make defences next to miners - even just the cheap ones.
The other thing is to always make sure you send teams of units out that can defend against everything - anti-air as well as anti-unit and anti-tank. Oh and use the hotkeys! Hope this helps.