Find more ways to cue it and click it for the desired behaviour, in easier circumstances. You can click for many different behaviours, whenever you happen to notice them, without confusing your dog. If you have more than one dog, separate them for training, and let them take turns. If you get mad, put the clicker away. If you are not making progress with a particular behaviour, you are probably clicking too late.
Accurate timing is important.
Get someone else to watch you, and perhaps to click for you, a few times. Above all, have fun. Clicker training is a wonderful way to enrich your relationship with your dog. It is a popular college and high school text, the basic training guide for all zookeepers and marine mammal trainers, and a favourite resource for parents.