If you’re an inexperienced taster, there are probably some grape varieties and wine styles with which you are still unfamiliar. These are potential traps in a blind tasting - you might taste something unfamiliar and mark it down because you think it’s a strange example of something you know well. There’s no way to avoid this - even experienced tasters get things wrong.
An eminent wine critic was once asked if he’d ever mistaken Bordeaux for Burgundy. “Not since luncheon”, was his reply. Try to take mistakes in good humour, as they are an important part of the learning process.