Probably you just need to learn a little bit about how the AI works. One way I did this myself was to play lots of 'Custom Games' against multiple AI opponents in different maps and with different rules and cards and whatnot. You can find the link to start a Custom Game at the bottom of the 'Single Player > Play' page. It used to be more prominent, but now it's tucked away in the lower left corner for some reason. Anyway, if you can't find it right away, here's the link: https://www.warlight.net/SinglePlayer?CustomGame=1
After you play, whether win or lose, use the History feature in the game to watch the entire game and see how the AI plays. You will soon start to see patterns, and then you'll be able to use those patterns to beat the AI much more easily.