DO's and DONT's in competitive multiplayer games
1. Fleet comes first
If it's not 1, it means somebody else has more fleet, meaning you quickly need to build more ships.
If your fleetrank is 1, then you have some room to do some research, but don't forget to still build more ships, else you will fall behind eventually.
2. Use Scouts
3. Build counters
Every unit in this game has a counter. Since you do use Scouts, you know what your enemy does. React to it and build the required counter units.
4. Do not rely on a single shiptype
5. Expand aggressively towards your enemy
Ideally you want a planet right on your enemies doorsteps. At such a planet you build a couple of repair bays and frigate factories.
Don't worry much about juicy planets in your backwater you didn't colonize. You can always do that later with a smaller, second fleet. At the same time your primary fleet will keep the enemy very busy.
6. Attack early, attack often
During the time it takes him to move his fleet to the planet you attack, you can often destroy a couple of buildings.
If the odds are against you, you can easily retreat to your doorstep planet and quickly repair. But don't wait long, go attack again immediately, preferably on a different planet.
This applies especially to Illuminator spammers. Having 50 Illuminators at home does you no good. But having 50 Illuminators divided in 2-3 smaller fleets harassing your enemy does.
7. Micromanage your fleets
8. Do not build static defenses
In addition, fighters, bombers and at least Vasari Assailants (possible other races long range ships too) can take out turrets without turrets being able to fight back at all.
There are exceptions to this rule, but I'll let you figure out the situations in which turrets can be helpful on your own.
9. Know when to retreat and when not
For example, never retreat if your enemy has a Phase Jump Inhibitor. While your ships spin up their jump drive, they'll be totally helpless and your enemy will destroy your ships one by one.
Likewise, do not retreat if your enemy has jump disabling abilities. For example Vasari can use Subverters and their colonizer capital (also called Space Egg or Space Whale) to prevent enemy ships in a quite big radius from jumping.
If you still have to retreat, take out the PJI or the jump preventing ships first. Alternatively, spread over a huge area, don't clump up your ships. Or sacrifice a few of your ships and only retread half of your fleet.
Whatever you do, if you flee in such situations, you will have heavy losses.
10. Find ways to disable enemy phase jumping if he tries to flee
11. Use the black market
Especially TEC players should like the market I think, they should have excess credits and lack resources. So use the black market to your advantage.
Assign hotkeys to quickly buy and sell metal and crystal.
11. Dear TEC players, forget about early trade ports
Basically trade ports take too long to pay off, building them early on leaves you with just a small, vulnerable fleet and you might not survive long enough to enjoy the benefits of trade ports.
12. Capture the neutral mines
Over the course of the game, check after your mines once in a while and recapture them should your enemy have stolen them from you.
13. Learn from your mistakes and adept