The focus on this shot is right!
Sadly, if the light rays doen’t exist in the first place, then there’s no way to amplify them in-camera. Perhaps perspective and what you include behind the sunrays may make a little difference, but the pictures you saw in the calendar were only that pronounced because they really were that pronounced in real life.
Having said that, there is a way you can amplify or create sunrays artificially in Photoshop. Start at about minute 38 in the replay: https://www.lenspiration.com/video/webinar011618/