Although I've been playing chess for years I have never looked at it as a serious game. I lack opening knowledge and "variations". Well my question is, does chess have a side where predicting the next players movement or determining the opponent's play style can determine his next move? I have almost always been looking at the best move my enemy can make.. hmm..

I'd say that the better you are, the better you'll be able to see the possible 'good' or 'best' responses. If the opponent doesn't choose one of those responses, then you can take advantage of that by either continue to gain a positional advantage or go no the attack because something has been left vulnerable.

The better the player, the more likely it is that you can accurately predict what the responses could be. There are usually only a handful of good moves, but a bad player can find any number of odd ball moves that are totally unpredictable.Yes, but are you good enough to recognize a best move?

The best move you can see is probably not the actual best move. If you can really see the best moves, you'd be a very highly rated player and wouldn't be asking this kind of question.

I am not highly skilled and it make sense that you should be one if you can determine the best move your opponent can make. I try to look for it but I still lack experience... Opening knowledge is one of my weaknesses... Can someone point me in the right the direction?

As you gain more chess understanding, it will be much easier for you to know what will be your opponent's next move. Let say you know pawn weakness, and in your game you have an obvious pawn weakness(lets say you have an isolated pawn that is easy to attack and pressured by his rooks), because of your chess knowledge about pawn weakness, it will not be hard for you to predict the 90% possibility of him moving his rook to pressure your pawn.

Yep, it just takes time. The more time you play, if you are studying and evaluating your games, you'll begin to learn what moves are good and for what reason.

As you learn what moves are good or best moves and the reason why the move is so good, you'll also learn why other moves aren't so good.

Opening knowledge shouldn't be your main concern. Most people think that opening knowledge means memorizing lines. If you want to learn an opening and memorize what to do when you run into a traditional opening, then I'd suggest picking up an e-book or two.

The basic idea is to make a claim on the middle squares of the board while developing your pieces (knight and bishop as well as queen) and connecting your rooks*. The player who develops his pieces to good squares first is the one to have initiative and the advantage. Through game play and looking at openings you'll see where you'll generally want your bishops and knights.

*Of course this is just a generality, sometimes it is actually better to leave your king in the middle.