take a look at this thread.
https://forums.sinsofasolarempire.com/305565it's not strategy but it gives you a decent bases for how things are done, there's also link to sheets of stats that are more usful desciptions than the manual.
that's the ships, as for economy... simply, make sure you upgrade civilian structures on your planets asap, more people = more taxes. also research the mining and planet upgrades to boost resources.
the games really involved, i find, and it's all to easy to get stuck in one part of it. e.g. watching a battle instead of improving planets, research, pirates, etc...
i find that when i keep an eye on everything, my games alot better.
also, if you find your self under attack, you don't have to dig and defend to the last, do enough to make it hard work for him (increase planetary defences), but find another route to him to get some pain flowing his way

you may lose a planet (but it's usually a front line planet and not as developed as your home planets), but you could take out all his tech/trade centers if he doesn't pull back to defend.
sins is balanced and open enough that the usual strategies can be applied.
hope that helps, feel free to ask any specific questions
MrL