Dark Fleet is not so impossible to pull in 1vs1. But you cant just rush to it and hope it will save you.
A strategy that i have been working on based on 1vs1 dark fleet and seems to be working preaty well, allthough it still needs testing and tweeking is this:
This strategy works a lot better against the advent then TEC so i am only going to talk abaout a 1vs1 vs a TEC player.
The main strategy is to be very aggresive in the begining and get a small empire going and then defend till dark fleet.
Note

/y means x military research centers/y civilian reserch centers
You begin by getting 4 navigators and going for extractors. You should build al least 4 navigators but the number should be something like nr_of_navigators = no_of_planets_with_free_extractors+1or 2 more. You send 1 streight to the enemy's home planet and the other to get the free extractors.
Go for 1/0 then go for a fast assailant/skirmisher army (use the fact that vasari get there LRM frigate at tier 1, the army should contain more assailents that will be the damage dealers and a couple of skirmishers that will be the tanks) and the Korthul + a colonization frigate. You could go for other capital ships but i recomand this one. After that go coloniseing. At this time the enemy fleet should be on the move. Allways keep a navigator close to the enemy fleet - you should allways know where they are (you may lose some navigators , but with good micro it shouldn't be too many), and also have another navigator scouting their planet to see their tech level.
The next move depends on the enemy. If the enemy goes for planet colonization go for a 1/4 to get tradeing centers. If the enemy is more aggresive got another militari center and get restauration or sentinels( this is a grate ability that makes the skirmisher a VERY powerfull tank). These first harrasment attemps should be easily defeated, the only unit you should be afraid of are Javelins so these are your main target, but being so early in the game the TEC player should not have a lot of them and because you started you assailants production earlier then you should be ok. Also skirmishers with restauration are a lot better then cobalts and become very good meat sheilds.
After this you should have gathered arount 4-5 planets (usualy 4 but on some maps you can get 5). You should chose the planet not by what they are(ice/astoroid) but by how the front line is going to look. You should be able to have only 2 choke point. Now start defending, this is the point where Javelin spam is going to hit its maximum so start bunkering up. Turrets and repair stations work greate. At this point you should be 2/4and have assailants, sentinels, skirmishers with restauration and trade stations available. The defences on every choke point should be 3/4 turets for 1 repair station. Now dont build turrets and units blindingly. Scout your enemy's army (sacrifice a navigator if you have to) and build units acordingly, asses the enemy army's strenght and only build defences when you think you need them.
Also getting the Korthul to level 6 is great, will mean the end of Javelins.
Once you get trade centers on all planets and defences on chokepoints go for the dark fleet. Many people said that the resorces needed for dark fleel make it not good for 1vs1, but that is not entirely true. Concidering the resource rates from 4 planets + tradeing post (can also add a rafinery if needed) you can gather the resources to build 8 research labs, all the research needed for dark fleer lvl2 and 5 phase gates, in 15 min. And thats alny because of cristal. Credits and metal are colected a lot faster, so if you use exces metal and credits to get cristals you should be ready in around 12 min, considering you already have 4 research labs build, the time goes down to 10 min.
Now the real time in witch you will get darc armade depends on how much resources you invest in your army and defences. So if you use 50% of income tecking to dark fleet. It should be done in 20 min - the real time will depend on how much defences your enemy forces you to make, usualy varies between 15 - 25 min. After dark fleet you preati muc know what to do.
From 5 gates when the research is ready you will get around this army:
3 skirmishers
12 assailants
9 enforcers
5 sentinels
5 transporter
The most importand parts of the strategy are :
- allways scout, se what army the enemy has and where it is
- use the costeffectiveness of defences to compensate for weaker units and smaler income
- allways adapt to the enemy dont just build the same army over and over.
- allways micro your units, vasri have less units with better hp so microing them is not so hard.