I'm not a big solo player, as fortunately I have a local group of mates to get games in with. But on occasion I have played solo games.
Often I have found they become a bit mechanistic, and all I am doing is rolling dice, and stuff just happens.
But I have found with the Dungeon Saga board game, this plays pretty well solo - partly because it has fairly short, time listed scenarios with an obvious goal, and the party of adventurers are meant to win, so a bit of bias is allowed, and I have found that I play the game a bit slower and think through each turn. So my suggestion is have a scenario, perhaps even a mini campaign, and play the game by playing each side properly in each turn (even if you favour one side, actually think about the moves each side is making).