Walling against the AI never works
If it encounters a wall segment thats roughly 5 square long, and it hits middle, it'll often just blast its way through. I've seen it do that to its own walls repeatedly...
Obviously was added to prevent the ever useful Warcraft 2 tactic... walling around the AI so it can't do anything (War2 AI never attacked walls, at least not directly.)
The Megma well is extremely useful. Once fully upgraded, it will give 150 ore, flat. Always more then a double rare flat.
On Eden Starship 1, I find its often better to have another common ore mine, then a rare one. What use is the rare if you don't have enough common to build anything?
With the extra mine, you can spam lasers, Railguns, and EMP like mad.
Lots of EMP lynx will take care of ANY amount of Tigers, particularly if you take them out one by one enroute.
While very hard to do, if you can manage it, take one base out before it can fully dig in. Removing the back base they often build is easy. While far, it is also the last built, giving you ample time to destroy it. This lessens enemy attacks by 1/3, making it FAR easier to survive.