So far my main strategy of taking out a system is to just blob my entire fleet at the AI. This is mostly successful, if it does not work, i just do it again and again until their defenses fall (verdun anyone?). I cant help but feel like there is more to this game than I am noticing.
This is a common strategy and it definitely works in some cases. There are definitely some situations it won't work as well in:
1) Planets with an AI Eye (blobbing starships can sometimes handle this, if you have enough starships unlocked)
2) Planets with an Ion Cannon (raid starships are a good counter to this).
Also, in my opinion, much more of the fun in the game comes from strategizing not how to attack a single planet, but rather which planet(s) to attack on your path. You have to carefully consider the following factors:
1) Goodies (ARS, fabricator, advanced constructor / factory, etc.)
2) Resource income (do I want the planet with 8 metal harvesters, or 2?)
3) Strategically defensible locations (whipping boy / chokepoint)
4) Which AI planets you'll be putting on alert by taking out a planet
5) Current AI progress and/or pending waves (is it too high? Do I need to instead use my fleet defensively to avoid death or significant pain in T-minus 2 minutes?)
Also which planets you don't want to take, but you want to neuter or destroy things in, for some of these reasons:
A) Too many guard posts on an alerted planet is going to end in disaster if left alone for a long time
B) Some planets need neutering to increase the distance your scouts can reach
C) "Negative" goodies (raid engines, alarm posts, ai eyes, ion cannons, hybrid facilities if you're playing with hybrid hives on)
D) Take out a warp gate, leaving command center alone
E) Take out a sizable threat fleet which is bound to end in ruin for you sooner or later