If your opponent is countering your counter too often, try using the jab instead of the hook or uppercut for a more likely hit.
If your opponent is stronger, it's all about dodging, blocking, and picking them apart with jab.
If you can get a clinch in when under pressure, do it - it can completely turn a bout on its head.
Strength is by far the most important stat. If you're stronger than your opponent, you'll always have a chance.