You will need a high level of dance training and experience.
Most choreographers start as professional dancers and often begin choreographing whilst still working as dancers, especially in smaller companies.
You would often start as a dancer by training at a vocational dance school, with a three-year degree/diploma or one-year postgraduate diploma in professional dance or musical theatre. Contact the Council for Dance Education and Training (CDET) for information on accredited dance courses.
Several universities also offer degrees in dance, and some courses specialise in choreography. To find a suitable course, use the course search on this site and check with course providers for exact entry requirements.
See the Dancer profile for more details about dance training.
As an experienced dancer, you could become an assistant choreographer after being a dance captain (who leads and rehearses other dancers but does not create steps), or through work experience with an established choreographer.