Let's see if I can shed some light. Also, if you're interested in a more tactical approach to how the game is played, you might try going to the After Action Reports area and reading through a couple of the AARs. I've got two that you might be interested in, the AI 9 through 10 run where I describe at a high level a number of different tactics I use through the game, and Disposable heroes, where I break down actions (sometimes to the minute) in an incredibly fast-paced game with overpowered ships.
There are only two critical components to this game, everything else is a tool in your hands to achieve it.
1) Find and destroy the AI Homeworld Command Stations
2) Do not lose your own Homeworld Command Station
EVERYTHING else in this game is a tool to those objectives. Either it's hurting you protecting your homeworld or it's helping you defeat the AI Homeworlds. A lot of those come in at oblique angles. For example, one of the options out there is the Neinzul Protectorate, who attack you if your economy is too high. This will affect you sideways because you can't rebuild as quickly if you hit their tipping points of when they will start hammering at you, or you need to increase your defenses.
So, with that in mind, everything else builds you towards the final objective.
Now, by default, Core Shield Generators are on. What these do is force you to take a certain # of worlds to destroy them. You need to take all but one of the A-Class CSGs which are also stacked up with ARSs, so you get more fleet ships. The rest as long as you kill one you're golden. There's A through E to destroy.
Then you need to handle the homeworlds. The homeworlds have a number of guardposts on them that all must be destroyed before you can destroy the final command station. These are protected by numerous ships far above your ability to produce, thus you'll need a powerful fleet (how powerful will depend on your AI levels and how often you annoyed it for reinforcements) to get in there and do enough damage that you've pushed forward towards the goal of killing it.
The balance in this game comes from riding the line between getting enough power to kill off the Homeworlds and not getting the AI annoyed enough (AIP, or AI Progress) that it overwhelms you during that buildup phase. You'll need to take 'jump' worlds, so that you're not doing deepstrikes with your fleet (over 4 systems away from a friendly/neutral planet). You'll need to take Factory IV worlds so that your MK III researched ships can also be produced as MK IVs, giving you that much more firepower when you go in after the enemy (Besides, there's B-Class CSG on each Fact IV, two for one!).
The game, as I like to call it, is making your OWN objectives to reach the final goal. You're trying to consume the game all at once. This won't work well, as you've found. Relax a little. Start with taking the systems around your homeworld as a safety buffer. Move to going for one of a kind resources, like Advanced Research Stations and Factory IVs. Continue to scout as deeply as you can. Use your fleet to open roads for your scouts to get deeper into the galaxy, so you can eventually find the AI HWs. Use turrets and other stationary defenders to protect your satellite worlds, or take over entire swaths of the galaxy and have a huge war on your hands. Depends on your idea of 'fun'.
Fun for me is driving Keith (one of the developers) a little nuts by doing off-the-wall stuff that works.
So, take the game in pieces. First, get your econ strong enough that you're not permanently waiting for resources while trying to build your fleet up enough to attack systems. Then get your fleet strong enough to attack the homeworlds by taking whatever out there gives you a stronger fleet. Finally, go blow up an AI or two.
Other than that... welcome to our little corner of the universe. Stay for the insanity, enjoy the tacos.