It's a complicated nightmare. I have played loads, and still are just scratching the surface. I think I got the basics resources down (Industry/Research/Economy), but the on the side stuff is complicated. (Tourism, Diplomacy etc.) Your best bet is just focusing on the basics first of the 3 resources. That way you can specialize planets to whatever you need, and just experiment from there. 

Pick a weapon path (Beam/Missiles/Kinetic) and stick to it should also help you fight the AI, and the rest is just what you are aiming for with your game really.

There are no "fixed" answers really, unless you listen to the colony ship spammer lunatic lurking these forums So, I suggest you just have fun, and then get back in here with specific questions later. Enjoy the complexity while it lasts

Its really not complicated at all, if you understand what all the core concepts are in the first place. Pretty much every game concept has its own section you can research.

Like military...

You research from 3 trees. The top is divided into the three weapon types, the bottom is the three defense types, and the middle is ground combat. Thats it.

Tourism, diplomacy, influence. they aren't any more complicated then this as far as the research tree is concerned. Tourism is a part of the economy tree. Just like the military example, it has three parts. Tourism, trade, and raw income. Diplomacy is in itself a tree, which is divided into three parts: government, relations, and influence. If your curious, government provides empire-wide passive bonuses, relations increase your standing with other empires and give you more diplomatic options, and influence increases the rate your territory grows.

All the tech trees follow this cookie cutter formula as far as I could tell. At first these trees can open up new buildings, components, and strategic options, but as you go down these trees they mostly just provide upgrades to your existing stuff, or increase bonuses you already have, or give you the opportunity to spit out another 50 supply ships to get that next 10% production bonus.

Some things I picked up on after a few games.

You really want to be conscious about what your colonies are doing before you research. Research techs aren't going to do you any good if your research colonies already have a big queue lined up. Production techs aren't gonna work so hot when you have your production colonies putting all their work into shipyards. Ya wanna keep them busy and queue up techs for your specialist colonies as they have room. Population works the same way. Its the most important stat, but farms are useless if the planet isn't nearly maxed out already.

Ya also wanna keep to your game plan. Focus on what makes you win the way you wanna win. The beginning is all about rushing colonies, so if its not helping you do that, its just filler. Later on you focus on techs which lead to the victory condition your aiming for.

On a side note, about that 10% bonus (talking about the starbases). I've found most orbital techs pretty useless except the +moral bonuses. More moral = more farms which means more pop, and pop makes the stat everything else is multiplied by.