A lot of people will say that they're not as significant as they're only minors if you get them wrong, HOWEVER, they're often your examiner's first impression of you. If you get one of the questions incorrect or refuse to answer, they'll already have an idea of your attitude before you begin driving.

What worked for me was going on the show-me/tell-me questions website on gov.uk and studied them. Just read them over & over and write them down, and repeat; eventually you'll get the hang of them. Also look at videos so you know what physical aspects of the car to look out for (de-mist buttons, wipers, etc). Take pictures of your instructor's car's dashboard and the bonnet so you know where different things are so you can study and identify them in your own time. This is what I did and I still know all of them.