I only have the demo so bear with me. But I can beat the demo on maso and can at least conquer one civ on suicidal before the demo ends. This is just my way of playing and i like it.

At the start when u choose the skills to focus on MAKE THE MAIN ONE DIPLOMACY. I know alot of people like defense and stuff but this lets u get what you want in the worst way. Ok off the bat just go as far up the diplomat tree as u can, it will differ each game because if i think im going to get setback i stop. Then get all the techs u can that only take up 1 turn. Btw put spending on 100% and try to keep your approval at 100 also u will lose money at first but hey. by then just trade and get everyones techs. Now its up to you because i just do watever at this point.

As for the colony stage do you best to get as many good planets as u can
low pqs can wait u will just get em back anyway when u rape the comp