Tech rush to sensors is still valid, except that now, since the engine thing and the fact that engine tech costs too much to rush research early in the game for minimal gain, I dont just buy one super fast survey ship in addition to my flagship to shoot around and gobble up three anomolies a turn.
Instead, thats actually what Im rush producing out early game, along with colony ships, so I have an entire fleet of surveys (plodding along at 3 or 4 speed) scouring the galaxy, so Im still pulling in 3 or 4 anomolies a turn. There may not be as many 2500's out there, but there are still plenty of 500 and 1000bc lottery tickets. There also seem to be many more anomolies on the default game settings in DA. Once they are all depleted the survey ships can be pretty cheaply converted to constructors or trade ships( in which case its actually beneficial that they run out of gas far away from my homeworld).
I dont bother with builing mine ships (the one you start with is fine), because its too tough to hold mines outside of your territory anways. Better to let someone else build them then flip them, or otherwise aquire them through conquest.
If theres a resource near my homeworld, Ill try to get a constructor on it, but I dont sweat it if someone else grabs it first. Gobbling up anomolies is much more important to my early game, keeping me out of the red with my defecit spending for as long as possible. If someone else grabs it the resource first, I know Ill have it soon enough

. If theres some abnormaly awesome collection of resources in spitting distance, I might assign a bit more of a priority to grabbing them, especially if ones a greenie.
I dont bother with colonization techs, except in rare cases where theres too good of an opportunity to pass up, and I can find a race actually willing to sell the tech to me. Colonization techs are too intensive to research early on and far too situational to justify it. Theyre much much easier to pick up later in the the game, often for free. My "advanced colonization technology" is "planetary invasion".