1. Articulate in hymns created before ca. 1800s.
2. Play legato in hymns created after ca. 1800s.
3. Lift the last note of the phrase for breathing.
4. In legato hymns, shorten the repeated notes by half (even in the middle parts).
5. Articulated hymns should not sound choppy at all. Adjust the spaces from organ to organ, from acoustics to acoustics (don't worry - it comes naturally from experience with multiple organs so try to get acquainted with as many instruments as you can).
6. In articulated hymns, make the meter paramount - aim for alternation of strong and weak beats by shortening the weak beat but making very little space between strong and weak beats.
7. Give the bass line more gravity by adding a little bit more of 16' and 8' stops (if needed).
8. If the soprano part doesn't sound strong enough out in the church, try playing it on another manual with the solo registration (alto and tenor could be played with the left hand).
9. Try adding a 16' stop for the soprano line to help the men hear the melody sounding one octave lower.
10. Sometimes people register the hymns too soft - experiment with Principal Chorus with mixtures and 16' reed in the pedals. This way people will feel that you're leading and feel compelled to sing from their hearts.
11. To make registration changes easier, play different stanzas on different manuals and prepare the stop changes ahead of time.
12. Leading is not the same as following - don't drag and play a split second ahead of the people (but don't rush).
13. The best way to lead is when you can almost play the hymn harmonization from memory. In fact, memorize one hymn and compare its performance with the others.
14. Make the last note of the stanza and the rest that follows very rhythmical - there could be a fermata on the note, but still keep counting. Then the congregation will feel confident when to start singing the next stanza.
15. Try to imagine how the congregation hears the result and not how it sounds next to the organ.
Apply these tips in your hymn playing and be mindful of the acoustics of the church. Remember, it's not what you do but what the people hear that counts.