It is hoped that you can GET MOTIVATED by the hymn either by hearing it sung, by sight-reading through it, or just by accepting the challenge.
Have you chosen a hymn that is WELL SUITED to your ability? Even if you have advanced keyboard skills, your first four-part hymn at the organ should be an easy one. If you prefer a greater challenge, be sure that you can finish it within a reasonable time period.
How do you judge the difficulty of a hymn for organ playing? There is no simple formula, but here are some of the important factors: