How do I handle a long gap on my résumé? - any advice?

I have been out of work for 8 months and worry about the gap. I have read a lot of threads here and could not find my exact situation. I am not sure how much to explain. What do you say in interviews?

I listed the volunteering and course under the same dates and kept the explanation to a sentence in the cover letter.

Keep your skills fresh and mention anything recent. It shows momentum.