Well, the middle game just is hard. Or at least, it is as hard as the opponent makes it for you. As a beginner, the main thing you have to do is to avoid making huge mistakes, hanging pieces for example. If you can do that and also notice when your opponent makes a mistake, you will win. And really, the same applies as you start playing at a higher level; it's just that the mistakes get more subtle, and you need more understanding to detect and exploit them. Hopefully that understanding comes with experience.
Try to analyze your games, especially the ones you lost. Understand your mistake. What could you have done that was better? If there is nothing, then your opponent was already winning, which means you need to look further back in the game for your mistake.
Hope this helps.
Rob
Most times the middle game beats me because the position is close, no weaknesses on my opponent and no strong attacks for me, nothing! Otherwise one mistake I'm down. Advise me about the Close Middle Game, PLEASE!