You should know what sorts of songs you're shopping for before you go looking for a songwriter. If you're a singer or their manager looking for success in modern country music, you need to appeal to a broad audience that likes modern country. They often also listens to Christian contemporary so you may want to get songs that overlap the genres.
A good bet is to focus on songs that are heavy on feelings of catharsis and nostalgia. When you turn on country radio today, those two feelings are what really seem to resonate most often. The followings topics in a country song are almost guaranteed to generate such emotions:
1. Broken Hearts That Find Redemption
These are songs about very traumatic heartbreak that seemed like the end of the world at the time. But later, through whatever mechanism the songwriter devises, the singer discovers that it wasn't the end of everything, only the beginning.
2. First Loves
It's a rare person whose first romantic partner ends up being their final one. So, songs about that first love have a broad appeal. Plus, they can be written very tastefully and in a way that appeals to the audience mentioned at the start.
3. Your Parent's Character Traits
"Honor thy father and mother" is one of The Ten Commandments. So, singing songs that point out the positive character trait of one or both of your parents remains perenially singable.
4. Small Town Drama
Most of these songs are lighthearted and fun and can really catch on. Think about it like this: it's the juiciest parts of Facebook drama, poeticized, and set to a couple of guitar chords. Anyone who's ever lived in a small town will get these songs. You want to make sure it's lighthearted, though, and never malicious.
The focus of these songs should be the discovery that you love your hometown after returning from a long absence. Often times the focus centers around someone who was popular and successful in their youth but then was forced to leave their hometown for whatever reason.
6. Love's Limits
Sometimes you really want to do something with a person but you just can't. It's a limit of love. Most people have experienced this in one form or another so it has a great chance of catching on.
7. Finding Faith
When paired with the perfect singer, a good song about how someone discovered their faith will almost guarantee success with modern country and Christian contemporary fans.
Reach out to a clean country music songwriter to get started.