Take Note

Whether inspiration comes from God, literature, art, someone else's story or your own, be honest. Record the inspired moment with truth as best you know how. Filling in missing colors or adding "artificial flavors" will reduce artistic credibility. Well selected adjectives and colorful language will come. For now record the moment and be honest.
Also:
Deciding to take a "mental note" of an inspirational moment, is deciding to forget about it. Document the moment with a photo, record a message on your phone, write/type a note. It doesn't need to rhyme or be award winning prose. It needs to be recalled. (I have a collection of melodies recorded on my phone that are NEVER meant to be shared :-)
Inspiration: 
Last night our family went out for ice cream. In the ice cream parlor Miranda Lambert's song, The House That Built Me, played above the chatter of the room. The girl behind the counter making waffle cones knew every word and quietly sang along as she worked. The smell of the waffle cones reminded me of pancakes with my grandpa when I was a kid. We waited in line for half an hour to get our dish of ice cream all the while smelling the waffle cones being made... And none of us got a waffle cone.
Now I can't say this is or will be a song, but I do know, as I watched her sing, it was honest. I was inspired to take note.

Experience

A song is a means to communicate with an audience. To relate with them an experience they too have likely had but did not articulate into lyrics and melody.
The actual song writing part of song writing typically happens late in the process. First comes an experience that provides inspiration to create a "short story" worthy of a listener.
      
With every moment that passes you have an opportunity to witness and record inspiration. The still calm of a late summer morning. A child's chalk drawing on the driveway that spills out on too the road. While dinning outside on the avenue, an old, beat up car passes by with a creepy doll strapped to the front bumper and the driver stares at you as they pass. (wish I was kidding....happened last night!) Hoping for an enlightened moment will more often leave you with less inspiration. Seek and you will find.

Inspiration

Inspiration often comes from experience. Experience doesn't have to be a moon landing to count as inspirational. When writing about your youth in New Jersey or recording in Nigeria, Bruce Springsteen and Paul McCartney recognized the inspiration within the experience for Born To Run and Band On The Run. Experience and inspiration happen in every country & every large and small town. Recognizing it, recording it & sharing it become the challenge.
God bless,
Joe Solay