I find that you have to bounce around the tech trees depending on the situation. Try to make the most of your first 50 turns by scouting as much of the nearby territory.

My main strategies when playing Vodyani are:

1st) Boost my Food and Dust Production for free popuation/upgrading my ark and ships early and Try to get the Ecologists Goverment

2nd) I start to ramp up my Industry to the point of getting access to market which also in turn buffs my Arks for more modules and try to Boost my Influence over minor factions

3rd) I start to focus on getting my medium ships/behemoth ready for attacking pirates/other hostile factions. If you have salvagers this is even better.

Then from here youll be around turn 50 or so and you can start focusing in 1 area, ive tried focusing on my Influence and building Alliances if Im outnumbered or I start building my behemoths. I find that if I focus too early on Behemoths its hard to even equip them becuase they take so much resources.

Here is a list of my general strat in terms of tech:

Planetary Landscaping (Food Boost)

Pev-Scale Accel (All must serve 2 module)

Botanical Scanning (Food Boost)

Umbiquitous Survelliance ( Military 2 buff, essentially helping your weak fleet in the beginning by equiping stronger lasers)

Unstable Isotope (Meditation Module)

Then at this point I may go for Market Place or I may go for Military and Medium Ships just depends if im comfortable. Sometimes you get screwed over by being next to Cravers and they come for you. Good luck haha!