In a conflict with any alien civilization, the weather will be the main enemy. As on terrestrial-based wars, weather and operational environments play a key strategic role within the dynamics of the conflict.
So-called "General Winter" was a key reason for the defeats of Napolean's Grande Armée in Russia as well as defeat of the German Wehrmacht more than a century later. In the 1200s, a
Mongol invasion of Japan was wrecked by a Typhoon giving rise to the Japanese term
Kamikaze, or "divine wind." Another armada which was impaired by a storm was the Spanish Armada in the year 1588. Likewise, other environments such as jungle or desert have unique challenges.
In a war between alien civilizations, the party which is fighting in an environment closer to its own "standard conditions" has less strategic impairment than the party which has a greater difference, all other things being equal. But of course on alien planets and space conditions, one has to contend with added considerations such as gravity and radiation of the battlespace. oh, and potentially toxic or no atmosphere to breath. The greater the difference from standard conditions, the more logistics and technology would be needed to just maintain presence (thus it would be mainly fighting against the weather just to survive). So when planning engagements, the side nearer to fighting in its own standard conditions would have the relative advantage. In the case of being the weaker or technologically inferior party, the strategy would be to engage the enemy in environments which negate or greatly limit them on what they can do and that are closer to one's own standard environment. One would want to bog them down with logistical problems as much as possible.
