What has most helpful in writing songs for your local church?
I was watching Bruce Springsteen on Storytellers recently, and he spoke about how you never know when creativity will "pass through" so it's your job to be ready when it does. I think there is something profound about being ready for the Spirit of God to move, rather than attempting to force Him into your calendar. To be ready, you have to see writing as a discipline, not just a whim, or a day that you feel like it with a little space on the schedule. Do it when you feel like it. Definitely do it when you don't. See it as brushing your teeth, not visiting the dentist.
BIG IDEA: Songwriting is a discipline.
Vary your inspiration. Don't listen to the same two records 24-7 when writing or your stuff will always sound like someone else's stuff. Inspiration is necessary, imitation is nugatory. What are you trying to say? What is God doing in and around you?
Find a location and time that stir you. It's hard to pick out melody at the local coffee shop, but that might be a great place for lyrics. If you're a zombie before 10:00am, don't slate that time as "creative outpouring". Some write better with others and some by themselves. Do both.
Know the channel. Are you writing this for yourself? Your family? Is this song meant for the Sunday stage? I would argue there are going to be slightly different criteria depending on the format you plan to deliver the song. I strongly discourage trying to write for the global church unless that platform has been given to you by God (and confirmed by those around you), but there is a whole generation of worship leaders trying to be the next _______. Faithfulness is what we are called to, not influence.
Lastly, present your song with printed lyrics to a few people in your life that are theologically astute. It's even better if they aren't artists (although anyone who crafts sermons is doing artistry). Receive what they have to say with humility. If your song is for the church, clarity matters. We should strive to say timeless truths in a fresh way, but we can confuse people while trying to capture mystery. Songwriting for the church is a delicate dance.
This quote list from the world's best songwriters is worth a read.
Bob Kauklin's "Worship Matters"
Paul Zollo's "Songwriters on Songwriting"