What to avoid in marinades?

As a food enthusiast, I'm always curious about the finer details of cooking. When it comes to marinades, I've noticed that some recipes can turn out better than others. Could you elaborate on some common mistakes or pitfalls to avoid when preparing marinades? For instance, are there certain ingredients that don't mix well? Should I be mindful of the acidity levels? Or are there any specific techniques that could enhance the flavor of the marinade without overpowering the meat or vegetables? Your insights would be greatly appreciated.