The thing is, none of those headers are even necessary. For example, replace "Beginner Class" with "AIKIDO", remove the "Regular Classes" and "Come Visit" headings, enlarge the text, and you've already improved the poster.

For bonus points, pluralize the days ("Tuesdays 7:30 p.m.") and separate the phone and URL from the address a bit.

The point is, the information is self-describing. It doesn't need a header to announce what it is.