Noob Seeking Cultural & Diplomatic Assistance

No matter how you want to win, you need to have a decent military rating. When your rating is low, other civs will dislike you, they'll give you bad deals, relations will lower, they'll demand tribute, and they'll attack you. When your military rating is high, they'll like you, they won't attack, they'll give you better deals, and they'll even give you gifts.

Military rating is something like attack + defense + hp/10 summed over all your ships. So you can inflate your military rating by building ships that are cheap but maximize this formula. Take a cargo hull or a huge hull, and fill it with a good weapon. These ships will be useless for actual fighting, but they'll cheaply boost your military rating enough that you'll never have to go to war. (No matter what your strategy is, design your own ships. The core ships are entirely useless.)

Other ways to make civs like you:
Before the game, put points in the diplomacy ability and pick the populist party.

On the foreign adviser screen, look at the "report" tab for all the reasons why an AI likes or dislikes you.

Increase your diplomacy ability by researching the diplomacy branch of the tech tree, and the government branch, and the ethics branch.

Build the diplomatic translators and don't trade them away. Build the galactic showcase and the galactic bazaar, and the spin control center.

Give tribute whenever an alien asks for it. Give them a free gift if their relations drop below neutral.

Research the trade branch of the tech tree and set up trade routes with the aliens.

Don't boost your influence ability until you're ready to max it out and start flipping planets. Close borders and alarming influence annoy the aliens.

Choose your alignment to match the alignment of aliens you wish to please. Or choose good alignment because then good and neutral civs will like you.

Do all that and you'll dominate the diplomatic part of the game. Developing a powerful economy, efficient production and research, good ship and fleet design, and warfare are other ways to succeed.

i think you mentioned the problem yourself. you research sporadically, picking only techs that are quick to complete. ever hear of 'jack of all trades, master of none?' set up your race with a a few abilities that go well together, and a govt that enhances that build. as for starting techs, i generally get as many engines as i can and then whatever takes me evenly to 0.

in game, instead of researching all the quick stuff, look at what you really get for each tech, i mean think about the direct effect that will have on you, instead of just having a vague idea of what you're upgrading each time. aside from weapons, of course.. they pretty much just get smaller every level and do more dmg every 5 or so.

tbh recently I've been using research as my dump stat and just picking up a little diplomacy, and then getting diplomatic translators real quick and trading for all the techs other civs get and only researching a couple things thye don't cover .. like entertainment. btw whats up with that shit, the other civs dont -ever- get entertainment.

sorry that bugs me

the thing the other guy said about your military strength is true, too. your military power affects politics bigtime. i generally like to grab laser V from one of the enemy civs after a little bit, cause they always have it. then research a couple levels of miniaturization and slap six or so of em on a small hull. build a couple here and there, checking your "stats and graphs" tab of the civ manager to compare your military strength to other players. as long as you keep it near theirs, you won't be bugged for tribute, and if you keep it above theirs, you get tribute from them

hope that helps

edit-sorry for the wall of text, i've been playing this game single player so long without talking about it .. lol.