It's playing in the corners, knight's moves, shape, connections, playing towards the edges, life and death, liberties, etc. As if you tried to map go tactics to this game.

I tried that too at first but didn't do very well against the hard AI. (Easy seems pretty random and easy to beat with anything). It took me a while to realize you need to throw out Go and find the tactics inherent to this game. I've found success counting adjacent colors and making moves so that I maximize the opponent's exposure to my color. The other thing to think about is what stuff you will automatically capture without needing a move. Some moves are completely unnecessary.