The AI Opponent, affectionately known as "The Brute", lives up to his name - he is conservative, efficient and very hard to beat. Here's a quick guide with some basic tips to assist with beating him.
Avoid positions where the opponent can attack two of your Magni by placing one of their Magni - this is called a Double Attack. In the following example, Blue could place their Magni in the indicated hex and claim a point by winning a skirmish with Red's Magni:
However, now Blue's Magni are in the perfect position for Red to play a Magni with northeast flanking attack and central attack values greater than 6, and Double Attack Blue's Magni:
Red gains two points for this move, meaning Blue's earlier move has proven more advantageous for Red than themselves! To avoid this, Blue could have placed their Magni in a hex that isn't adjacent to their first Magni, or played a Magni with a higher central attack, forcing Red to commit a much stronger Magni if they wanted to perform a Double Attack.
Try to keep up with the opponents points as much as possible - it is harder to come back from a larger deficit in the late game as it is usually easier for your opponent to play defensively
Use your weakest Magni first, reserving your stronger Magni for late game or taking advantage of a Double Attacks on your opponent. Keep track of you and your opponent's star budget on the field. A player who uses their strongest Magni first has no surprises left!
Don't use the Aggressive preset - the other presets have higher win percentages
Hopefully you see some improvements in your play with these basic tips. Good luck, and have fun!