You can click the heading's of each tech tree in the Research Menu to reveal what techs are offered to you. From there you can actually click the tech name and get a desciption of what it does.
To answer your question, always scout local systems first so you can see what type of planets are orbiting in them. Also, should a Space Eel or Crystal or
be guarding the system, you only lose a scout and not your valuable colony ship.
The first research should be towards the "all techs" categories. If you haven't noticed already, when you highlight a tech with your cursor - a green arrow will point to the tech from the left side. You are choosing to research that one tech out of the three offered in that field. The other techs become lost, unless a rival Race researched it & offers to trade with you. The only other way to get all three techs is to:
1) have the "creative" attribute for your race. You can get that by playing as the Psilons or by downloading the v1.31 patch which allows you to create a custom race. I highly recommend getting this patch!
2) by default, all races can research 4 "all techs" categories. These categories are always the same, you cannot choose which ones they are. However, they are essentially the most important, and that's why you get all the techs within them - including: nuclear powered engines & nuclear missiles/bombs, laser rifles/cannons for troops & spaceships, freighters to transport food between your systems, basic fuel cells, etc. These 4 are called Chemistry, Nuclear Fission - followed by Cold Fusion, and Physics.
After those are researched you can build colony ships, outpost ships (they let your ships fly further away from your controlled systems), freighters, and basic military planes, as well as troop transports for ground invasions.
The next part is up to you. For production, I believe the tech tree name is construction that you want to follow. Early on you have the option of building a missile base or automated factories. Whichever you choose, you can likely trade it for the other when you make contact with a friendly race. I usually wait until first contact is made before choosing. If they are friendly, I go for production, if not - I go for defense. Missile bases are very, very good early on in the game & can successfully defend you from almost all attacking fleets without the aid of starships.
The other categories to look at early are the biology, computers, & chemistry trees. Biospheres are needed early if you happen to have small or tiny planets where population maxes out early. It can be found in the biology tree & will grant a +2 to population on each planet it's built on. The chemistry tree provides fuel cells that allow your ships to travel further, as well as more powerful missiles and stronger armors. The computers tree has a wide array of options, the first being a standard targeting computer which increases the accuracy of your weapons for a cheap research cost. I usually grab that early as the next option, optronics, includes the first research lab.
In a nutshell:
1) Research Chemistry, Nuclear Fission - followed by Cold Fusion, and Physics so you can build the basic ships. While doing so, explore with your scout.
2) Research Electronics - followed by Optronics, and start building a research lab. While doing so, your scout should be about done exploring the local systems - so send out your waiting colony ship to the best planet.
3) Keep research going, but focus more on production - get more colony ships & a few freighters to keep your people fed! Research should be in Adv Engineering - followed by Adv Construction. Adv Const will have the option of automated factories or missile base - hopefully you will have met a "neighbor" by now and have an idea of which to make.
4) Have fun!
PS) housing is pretty worthless & trade goods only helps later in the game, just like in Civ; missiles are awesome in the early game!!!; expand the Empire; trade, trade, spy, trade; make your own races/ship designs - that's half the fun & well worth it!
Don't bother with trade goods if you have enough money, housing is also usually unimportant.
