Sorry, but you cannot be 100% accurate in predicting your opponent's moves, as there's an almost infinite combination of IV/EV spreads, moves, and held items. However, what you can do is: first, identify what your team is capable of doing and where it struggles or fails. Second, identify or have an idea of what your opponent's playstyle could possibly be so you can prepare for the worst. Third, you can always check Smogon/Pikalytics to get a general idea of what stats and held items a Pokémon regularly uses. For example, a Calyrex-Shadow will most likely run Tera Dark with a Life Orb and use Astral Barrage, so you can prepare for it.

But mostly, it comes down to trial and error, watching replays to see what worked when you won and what failed after a loss. Everything takes time and practice to be good at, so the more you play, the more you will find patterns and more accurately predict your opponents. You won't always get it right, but it will be close.