I'm a bit of a weird player, but here's what worked for me:
I played the tutorial only long enough to grasp the basics.
Then, I played a couple dozen games over several months, but only for the first half hour to an hour. I'd cap a planet, or test basic strategies against waves, or focus on scouting as much as I could. Really, this is a perplexing game at first and I was just puzzling out all the game mechanics. This was sort of a game in itself and I realize that I was actually kind of having fun figuring it out... but this would be an insurmountable obstacle for a lot of other players, so I'm a bit odd that way.
(IMO) The manual and the tutorial are (were? it's been a while) particularly bad at giving a concise description of reinforcements, and it's the one thing I'd recommend reading up on in the Wiki, but even there the basics are scattered among a few entries.
So basically, if you're like me, in that you
don't sit down to a game with a knife and fork and intend to figure the whole thing out over the course of several consecutive hours, here's what I recommend:
1. Start a new game with all the options you find intriguing, ON. Regardless of how intimidating they may be.
2. Play until it gets confusing, then pause and try to figure out the situation.
3. Quit if it stops being fun, and put it down for a bit, then pick it back up when you get curious again.
Eventually you'll get the flow. The above steps might repeat a bunch of times in an afternoon, a week, or as in my case, over months.
I have this wooden puzzle on my desk. I pick it up now and then. Someday, I'll solve it.