Would any skill from those games translate over to sins?
From Endless Space no, because thats turn based and Sins not..
One thing I don't like about sins is its lame tutorial (needs to take notes from extra credits) and said learning cliff. And unlike ES it's not turn based, so I don't have the luxury of being able to read though the tech tree and meticulously plot out what i'm going to do and weigh my options-or its tooltips for literally anything clickable.
Tutorials are extremely lame indeed, but after some tries against easy AI you should at least get the basics of the game. And most things are logical like upgrading your planets population to not lose credits to underdevelopment, always build extractors to gain their income, build ships to win battles etc.
Oh, and you can pause the game by pressing the pause key, the default key to pause the game, so you have time to read, think etc, just dont ever do it online.
As for actual gameplay what are the ins and outs of the Vasari rebels? I tried Advant and TEC, but the vasari just clicked. And also I have an unhealthy obsession with their starbases. They move! They're like a pocket titan for your gravity well!
I suggest getting familiar with the other two first. VR is not an easy faction to master, but if you insist.. Colony capital ship (Jarrasul, the egg) + some light frigates will do in the beginning, expand fast, upgarde new world population to get rid of negative income, and ONLY build starbases if you must, say, when you reach your opponent and he has a stronger fleet. Or if you attack him try to build one at his gravity well, it can cripple the AI if you manage to finish and upgrade it.
General tips for every faction:
0. Start with quick start enabled. Trust me, it helps. And pirates off, they have a strange armor type that makes cheaper units bad against them, and can wreck your game early.
1. expand fast with two colony fleet (a colony capital ship and some light frigates, the second fleet is a colony frigate and some light frigates), upgrade the newly acquired planets to nullify uunderdevelopment tax and build extractors. You should own a big as possible territory, turtleing in this game is the worst idea. In 1v1 agaist AI you should own at least half of the map.
2. Max out your initial fleet supply but don't upgrade fleet capacity too much as it destroys your economy. Only upgrade it if you feel your fleet is not big enough (so you have 8 frigates and a capital ship while the AI has 12 light frigates and a capital ship).
3. If you colonized many worlds and upgraded them, you may start building a fleet. Light frigates, Corvettes, Long range frigates are all good for this purpose. If your opponent has too many fighters, then build some flak as well but don't build too much, their damage modifiers are poor against almost anything, I was fooled in the very beginning thinking this ship is better than the other because it attacks more. NO IT DOES NOT.
Oh btw there is someone on this forum who may say build only flak, this is his fetish. But just don't do it unless you feel like experimenting.
4. Ignore unnecessary research. Skilled players are divided on what research is useful to get early on. For me the early metal and crystal income increase ones, the terran population increase researches are always good, unlocking necessary ship types are awesome as well. If you have an Ice OR a Volcanic planet next to you, get the research that enables you to get it, but you may just ignore these and get easier planets instead. But don't get the Ice planet research if you don't have any nearby.
Culture platform is good as well just don't build too many, instead try to focus on trade, that is more efficient.
If you have many ships and lots of money, you should put money in hull, shield, weapon damage, armor increase. These are all good, but shields are the least effective in this game.
5. If you can manage it, so don't have to put every coin into ship building, try to make planets always grow population. So if you see a terran planet get near 100 population, upgrade it further to grow bigger.
6. Scouting. You should always know where the enemy fleet is. Just send some scouts towards the enemy territory, to monitor his actions. It requires attention not to let fog of war reach 1000s of seconds (last intel from X planet). If you see the AI has dozens of ONE ship type, say, light frigates, your best bet is to build many long range frigates as these counter LF very well. When you want to build a ship, it's info card says what it is good against, or you may just search for the weapon type tables somewhere on these forums.
7. Don't build many capital ships. In this game until level4 or 5 they are worse than 50 fleet supply of frigates. Only build new ones if you lost your original free one, or your first one reaches level6. But it's better to have only one capital ship, and your second should be the titan.
I hope I wrote everything I wanted.