Basic Strategy Hints:

Use Additional Actions to Fulfill Objective Cards
If you have a difficult domination card, then additional actions will usually be helpful in fulfilling it. This will still be worthwhile, even if you have to spend points for these additional actions. Also try to do this early enough, so that you can benefit from the immediate effect.

Distant Stars Are Better
When taking a star, always consider its future population growth potential. Stars that are close to a star already owned by you or another player are bad.

Use “D” Fleet
On your first turn, put one of your ships into the “D” fleet so you can fly further.

Have a Strong Defense
Even if you want to play peacefully, build up a strong defense. Even STO players can switch alignment and then suddenly take your stars. A good precaution is to have a
ship at each of your stars within reach of other players.

Take Stars from Players Ahead of You
It is a lot more effective to take a star from a player who is ahead of you either in points or technologies than one who is behind you in both.

Last is Tactically Best
If you are later in turn order you will have a significant tactical advantage against players whom your are at war with. This is also useful to defend your stars, because you can then concentrate your ships only at the stars being attacked and do not need to spread them out.

Park Ships in Nebula
If you don’t know where to move some ships, then putting them in a nebula can be a good idea. It will give you more options in the next round because of the greater range.

Use Asteroid Systems
Make use of asteroid systems as much as possible to build additional ships. It is usually a good idea to park a ship in each asteroid system you can reach even if you are not sure yet, if you will be building ships this round.

Strategy tips in video format:

Advanced Strategy guides:

Overview of Strategies

Fleet Operations Guide

Turn Order Strategy Guide