You are now getting a handle on what you should be trying to achieve in the openings. So it should be equally clear on what you can do to frustrate your opponent. Any developing move that also delays your opponent's development is a good move.
Whether you are playing against a beginner, an intermediate or an advanced player, you should approach the game in the same way.
Your opponent may or may not approach the game armed with sound strategy. No matter you should play your own game. As you know what you need to do, equally you know what you should try to prevent your opponent from doing.