I always shake during beam, anything I can do to help that?

Whenever I'm in practice I usually stick everything and have no wobbles (I usually don't fall off the beam, my record for not falling is around 2 weeks) but whenever compete I'm a nervous mess. For example, a few weekends ago I got on the beam and landed my back walkover fine and then had a big wobble on a dance piece. It's mostly the stupid things. Is there anything I can do to help that or am I just bad?