Have to agree with everyone. Tough isn't very tough, it's a matter of focusing on production and research (ignore everything weapon related after space militarization -10% military production) and knowing how to keep the AI off your backs while you do it.
When they become anty, work on dipolamcy, trading , build a spin center on your best industry world. Trade for a good weapon (typically stinger or harpoon) with either a minor race hence saving research effort on space weapon and preceding techs, or an ally and start pumping those ships out at the spin center, that is enough to make you Number 1 in military. Then continue developing...
Because the AI colony management is still pretty bad (better than 1.1), you should be able to outstrip the AI even if you have fewer colonies (also you don't waste research/production efforts on unnecessary weapons).
Make a special effort to ensure your colonies have enough food to grow past their limits, every few turns check the colony management list, and order by population. Look for 'round' populations, specificly 5.0 billion, 9 billion, 11 billion etc, check that those colonies have enough food production, if not, go there and build a farm ASAP (buying one if you are rich). But don't build them until you have to.
I don't build multiple farms, instead when necessary, I prefer to research more advanced farms and upgrade the existing farm.
Don't neglect picking up morale improvements particularly when your population grows large or when you need to raise taxes...
If you have the time research and build xinathuium hull plating and dipolmatic translaters ASAP, because if you don't the Ai will and both are pretty good. The next one they go for is microbot repairs and aprhodiac, I don't find the former as important. The later I don't go for because when I play neutral I don't need habitat improvments which allows the latter.
Another one to grab fairly early is Tir-Quen training.... For all the others you can take your time.
These days I like playing the influence war, so I pick up the relevant techs (don't forget the government techs which add influence too) , build tons of constructors and Galactic achivements like Resturant of Eternity and Galactic show case, then start building influence starbases like crazy...
There is also an art in choosing the order to research plantery improvements, like factories ---> Industry sector... or labs ---->discovery spheres.
Generally, because the newer improvements are less efficient, you might consider waiting untill most of your colonies have finished building most of the tiles with the lower improvement.
For example, if your industry colonies still have a lot of unbuilt tiles, you might be be better off holding off researching manufacturing centers until most of the tiles have built enhanced factories.
I specialise a lot, so most of the time I find myself staggering my research, moving from researching industry improvements to research labs improvements to econ improvements and back again rather than researching 2 of each category in a row. The exception is the banks to stock market ....
Oh yes, don't forget to upgrading your mining bases, whenever you research a new level of factories!